## _wp10157

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---

### Purpose and scope
- Examines conditions for monetary integration in Africa and provides a quantitative assessment of costs and benefits of selected currency-union projects.
- Integrates OCA concerns (costs of a one-size-fits-all monetary policy in a heterogeneous region lacking fiscal federalism) with potential benefits from enhanced policy credibility.
- Extends earlier work (Debrun, Masson, and Pattillo, 2005; Masson and Pattillo, 2005) with coherent calibration, updated empirical estimates, and explicit modeling of substitutability between monetary integration and domestic institutional reforms.
- Explicitly excludes microeconomic gains (e.g., transaction-cost savings estimated as not exceeding 1 percent of GDP in the euro area) from the model.

### Key analytical contributions
- Full cost-benefit analysis of selected African monetary union projects within a coherent theoretical framework that:
  - Quantifies costs from asymmetric shocks and loss of monetary policy flexibility.
  - Quantifies gross benefits from improved monetary policy credibility and effectiveness.
  - Models substitutability between monetary union and domestic institutional reforms (e.g., stronger fiscal frameworks, greater central bank independence).
- Calibrates the theoretical model using updated empirical estimates and emphasizes asymmetries in institutional quality and credibility as central to assessing union viability.

### Main findings and quantitative conclusions
- Simulation results are "slightly more favorable" than earlier work but:
  - Net gains often uncomfortably small or negative for many potential members.
  - Net gains significant for only a minority of potential members.
- Modest or negative net gains reflect:
  - Slow convergence in fiscal policy performance.
  - Persistently low degree of regional trade integration.
- Improved monetary policy credibility could be achieved by domestic reforms without incurring union costs:
  - Strengthening domestic fiscal frameworks.
  - Enacting greater central bank independence.

### Model structure and core mechanisms
- Static, n-good, n-country region; open-economy Phillips curve where unexpected inflation raises output; distortive taxation reduces it; negative monetary spillovers proportional to trade intensity (ki, θ).
- Fiscal instantaneous budget constraint includes propensity to spend on socially wasteful projects (i δ) and resource-rent extraction (i ρ).
- Authorities’ utility (Barro-Gordon type) dislikes deviations of public expenditure and inflation from targets (i g~ and i π~) and variability in distortive tax rates; output enters linearly.
- Monetary union centralizes monetary policy in a common central bank (CCB) that maximizes GDP-weighted sum of members’ utilities; regional inflation reflects union-average financing need (M A FN).
- Central bank independence parameter i λ captures political interference: i λ = 1 full political control; i λ = 0 complete independence.

### Empirical strategy and calibration
- Calibration fits cross-country fiscal and institutional data over 1994–2005 and variance-covariance matrix of terms of trade and output over 1990–08.
- Recorded trade scaled up by 25 percent to account for under-recording of intraregional trade.
- Key calibrated/estimated parameter values (as reported):
  - c = 0.63735; Standard error 0.16294
  - μ = 0.376572
  - a = 1.20359; Standard error 1.7006
  - b = 2.33295; Standard error 3.2573
  - γ = 2.35337; Standard error 4.8626
  - η = 4.3213; Standard error 1.6642
- μ equals broad-money-to-GDP ratio across SSA averaged 1994–2005: 0.376572.
- Interpretation: monetary policy relatively ineffective in calibration — a one percent inflation surprise associated with roughly a 0.6 percent change in output (implied by c).

### Cross-section estimated equations (45 SSA countries, 1994–2005 averages)
- Inflation equation (as presented):
  - iAii FNA ,577.0399.0812.2
  - R2 = 0.207; p-value = 0.0028
  - Coefficients (standard errors in parentheses): (9.717)  (0.218)  (0.319)
- Revenue equation (as presented):
  - 
    iAiiii
    FNAFNFNrev
    ,
    109.0137.0547.0173.1
  - R2 = 0.473; p-value = 0.0000
  - Coefficients (standard errors): (4.969)  (0.111)  (0.185)  (0.162)

### Regional simulation results — welfare effects (percent of GDP)
- Welfare measured in percent of GDP equivalents; decompositions include monetary externality, fiscal asymmetry, and shock asymmetry.

- East African Community (EAC) — all five countries union (Table 7):
  - Burundi: Welfare Gain = 2.90 (Monetary Externality 0.81; Fiscal Asymmetry 2.36; Shock Asymmetry -0.20; GDP Share 1.87; Shock Correlation 0.17; FNA/FN 0.75)
  - Kenya: Welfare Gain = 1.40 (Monetary Externality 0.81; Fiscal Asymmetry 0.67; Shock Asymmetry -0.07; GDP Share 1.67; Shock Correlation 0.58; FNA/FN 0.92)
  - Rwanda: Welfare Gain = 0.64 (Monetary Externality 0.81; Fiscal Asymmetry 0.76; Shock Asymmetry -0.91; GDP Share 5.26; Shock Correlation 0.22; FNA/FN 0.91)
  - Tanzania: Welfare Gain = -0.30 (Monetary Externality 0.81; Fiscal Asymmetry -1.09; Shock Asymmetry -0.05; GDP Share 1.69; Shock Correlation 0.78; FNA/FN 1.17)
  - Uganda: Welfare Gain = 0.52 (Monetary Externality 0.81; Fiscal Asymmetry -0.16; Shock Asymmetry -0.14; GDP Share 9.51; Shock Correlation 0.62; FNA/FN 1.02)
  - Interpretation: significant gains for Burundi and Kenya; modest gains (< 1 percent of GDP) for Rwanda and Uganda; small net loss for Tanzania.

- SADC (including South Africa) — mixed results:
  - South Africa would likely dominate; correlations of terms of trade vary, some negative with South Africa.
  - Significant net gains mainly for more profligate countries; net losses for Angola and Mauritius.
  - Tanzania small net gain due to South Africa anchoring discipline; most countries, including South Africa, record modest net gains (< 0.5 percent of GDP).
  - Selective expansion of the Common Monetary Area (CMA) generally mutually beneficial (except Angola and Mauritius).

- ECOWAS (WAEMU + WAMZ) and single-entry exercises:
  - WAEMU average financing need (FNA) = 38.5 percent of GDP; WAMZ FNA = 33.4 percent of GDP. Within WAMZ: Nigeria = 31.5; Ghana = 45.8.
  - Nigeria’s unweighted average correlation of terms of trade: -0.37 with WAEMU, -0.27 with other WAMZ.
  - Full ECOWAS union: many members gain; only the Gambia is a net loser; two WAMZ countries gain > 2 percent of GDP; WAEMU countries’ gains roughly 1 percent or less; Nigeria extracts a small net gain.
  - Adding single WAMZ country to WAEMU:
    - No WAMZ country both increases its own welfare and increases welfare of all existing WAEMU members.
    - Gambia and Guinea would not gain from WAEMU membership in these restricted unions.
    - Ghana and Sierra Leone would gain by joining WAEMU but could lower existing WAEMU members’ welfare.
    - Nigeria’s membership could reduce welfare of Cote D’Ivoire due to output shock correlations.

### Sensitivity analysis (Table 13 summary)
- Parameters mechanically halved or doubled in turn: a, b, c, η, γ.
- Halving any parameter except c produces welfare gains qualitatively similar to base case.
- Doubling each parameter except a and η has little effect.
- Increasing a and η together makes independent currency relatively more valuable when shock asymmetries exist.
- Lowering c (monetary policy less effective) increases value of independent currency.
- Fiscal-policy-related parameters (b and γ) have less impact on WAEMU/ECOWAS welfare comparisons.

### Institutional, trade, and policy context
- Empirical literature finds high asymmetry of real (supply) shocks across African countries; some subgroups show higher demand-shock correlations.
- Trade effects and endogeneity: evidence mixed — monetary union can increase intra-union trade (factors reported include 1.7 and 1.7–3.0 depending on study), but even a doubling of intra-regional trade may not suffice in the DMP welfare model.
- Convergence evidence:
  - EAC and ECOWAS show greater convergence dynamics; SADC-wide convergence less favorable.
  - Fiscal convergence stronger for fiscal balance than for expenditure; seigniorage reliance declined across SSA.
  - Institutional quality shows some convergence but not uniformly; only EAC exhibits across-the-board institutional improvements.
- Official timetables (EAC, SADC, ECOWAS/WAMZ) appear ambitious; WAMZ and ECOWAS timetables have been repeatedly postponed (WAMZ postponed to 2015; ECOWAS currency target postponed to 2020).

### Policy implications and recommendations
- Monetary unions should be accompanied by enhanced regional surveillance of fiscal developments to minimize coordinated pressures on regional central banks.
- Domestic institutional reforms can substitute for union benefits:
  - Adoption of medium-term fiscal frameworks with binding numerical constraints.
  - Formal delegation of monetary policy to independent central banks with explicit mandates and guarantees against political interference.
- Design and feasibility of credible supranational institutions are crucial given modest net gains for many members.
- Financial stability considerations:
  - Coordination of financial regulation and prudential supervision needed to match financial integration and avoid unsustainable internal imbalances.
  - External anchors and guarantees (e.g., historical French Treasury guarantee for CFA) are difficult to replicate for new unions.

### Limitations, grey areas, and research agenda
- Model excludes microeconomic gains (transaction-cost savings, price transparency, trade creation) and offers a static picture of unions given current convergence.
- Important directions for further research:
  - Better measurement of institutional strengths and realistic capacity to implement credible reforms.
  - Modeling dynamics of monetary integration and conditions under which sub-regional unions act as building blocks.
  - Cost-benefit assessments in models with richer dynamics and panel estimation.
  - Study political economy of building credible regional institutions versus strengthening domestic institutions.
  - Examine implications of global financial crises and tail risks for union design.
  - Ensure financial integration is matched by integrated prudential supervision.

*Source: _wp10157 - References, IMF working paper content provided in the prompt.*

### References .............................................................................................................

### _wp10157 - References

### Purpose and scope
- Examines conditions for monetary integration in Africa and provides a quantitative assessment of costs and benefits of selected currency-union projects.
- Integrates traditional OCA (optimum currency area) concerns—the costs of a one-size-fits-all monetary policy in a heterogeneous region lacking fiscal federalism—with potential benefits from enhanced policy credibility.
- Extends and updates earlier work (Debrun, Masson, and Pattillo, 2005; Masson and Pattillo, 2005) with a more coherent calibration, updated empirical estimates, and explicit modeling of substitutability between monetary integration and domestic institutional reforms.
- Explicitly excludes microeconomic gains (e.g., lower transaction costs, greater price transparency, enhanced cross-border competition) from the model; notes that savings on transaction costs were estimated as not exceeding 1 percent of GDP in the euro area and are treated outside the model.

### Key analytical contributions
- Presents a full-fledged cost-benefit analysis of selected African monetary union projects within a coherent theoretical framework that:
  - Quantifies costs from asymmetric shocks and loss of monetary policy flexibility.
  - Quantifies gross benefits from improved monetary policy credibility and effectiveness.
  - Models substitutability between monetary union and domestic institutional reforms (e.g., strengthening fiscal frameworks, increasing central bank independence).
- Calibrates the theoretical model using updated empirical estimates and emphasizes asymmetries in institutional quality and credibility as central to assessing union viability.

### Main findings and quantitative conclusions
- Simulation results are "slightly more favorable" to monetary union projects than in the authors' earlier work, but:
  - Net gains appear uncomfortably small or even negative for a number of potential members across envisaged groupings.
  - Net gains are significant for only a minority of potential members.
- The modest or negative net gains reflect:
  - Slow convergence in fiscal policy performance.
  - Persistently low degree of regional trade integration.
- Improved monetary policy credibility and effectiveness—the key source of gross benefits from monetary union—could be achieved by:
  - Strengthening domestic fiscal frameworks.
  - Enacting greater central bank independence.
  - These domestic reforms could yield credibility benefits "without incurring any of the costs of monetary unification."

### Limitations, grey areas, and directions for further research
- Two important dimensions for further research are emphasized:
  - Better measurement of institutional strengths and weaknesses, and the realistic capacity of governments to design and implement credible monetary and fiscal reforms.
    - Understanding the scope for scale economies in institution building is important because effective institutions absorb scarce human and financial resources; scale economies would favor regional over national institution-building efforts.
  - Better modeling of the dynamics of monetary integration itself, especially the conditions under which sub-regional unions can act as building blocks for larger unions.
- The authors acknowledge that their model does not capture:
  - Microeconomic gains (transaction-cost savings, price transparency, cross-border competition).
  - Potentially large trade-creation effects of monetary unification (not modeled explicitly; qualitative impact noted as straightforward to assess).

### Literature survey and methodological critique (Section II)
- Reviews three main empirical approaches used in the literature to assess African monetary unions:
  1. Measuring asymmetry of shocks (OCA theory), often via VARs and shock decompositions.
  2. Comparing macroeconomic performance of existing monetary unions with non-members (influenced by CFA franc zone institutional structures).
  3. Monitoring convergence of macroeconomic indicators against entry criteria (inspired by European convergence criteria).
- Criticizes these approaches for not providing a framework to assess whether benefits exceed costs or to compare monetary union with strengthening domestic institutions; they also inadequately capture dynamic performance.
- Notes more recent papers attempt to address some of these issues.

### Empirical evidence on shock asymmetry (Section II.A)
- Many studies find real (supply) shocks across African countries are highly asymmetric, complicating a one-size-fits-all monetary policy.
- Methodological notes:
  - VARs and Blanchard-Quah decompositions are commonly used to separate demand and supply shocks; supply shocks pose greater problems for unions.
  - Bayoumi and Ostry (1997) use GDP-only VARs and benchmark African-country shock correlations against correlations among Germany, Japan, and the United States; they conclude African correlations are lower and thus provide little support for monetary unions based purely on shock similarity.
  - Horváth and Grabowski (1997) find supply shocks highly asymmetric but identify subgroups (Maghreb/Egypt, Western Africa—principally CFA, and parts of Southern Africa) with relatively high demand-shock correlations.
  - Fielding and Shields (2001) focusing on CFA zones find price shocks are quite positively correlated (similar across both CFA zones), while output shocks can display negative correlations; this suggests real-shock asymmetry is a concern even within existing CFA arrangements.
- Recent studies corroborate that asymmetry in real shocks partly reflects very different commodity-production mixes across countries.

### Policy implications drawn by the authors
- Monetary unions in Africa face nontrivial costs due to shock asymmetry, fiscal divergence, low trade integration, and institutional heterogeneity.
- Given the model results, policy priorities include:
  - Strengthening domestic fiscal frameworks.
  - Enhancing central bank independence.
  - Pursuing institutional reforms that can generate credibility gains comparable to, or substitutable for, those from monetary union—potentially avoiding union-related costs.
- Official timetables for major sub-regional projects (EAC, SADC including the CMA, ECOWAS) appear ambitious; for some projects (e.g., ECOWAS) timetables have been postponed repeatedly.

*Source: _wp10157 - References, IMF working paper content provided in the prompt.*

### conclusion for Eastern and Southern Africa, though they do find a few sub-regional

### _wp10157 - conclusion for Eastern and Southern Africa, though they do find a few sub-regional

### Shock identification and implications for optimal currency areas (OCA)
- Dynamic structural factor analysis (Houssa, 2008) offers an alternative to VAR models for identifying demand and supply shocks and can account for measurement error because it does not require estimating a large number of parameters.
- Houssa (2008) finds negative and low positive correlations of supply shocks and concludes that countries would find forming a monetary union challenging.
- Debrun, Masson, and Pattillo (2005) identify shocks to real output with terms of trade shocks; they find terms of trade correlations were low, and sometimes negative, for pairs of ECOWAS countries.
- Wang and others (2007) find that CMA countries do not exhibit consistently positive terms of trade correlations despite tight trade links and a long-standing exchange rate union.

### Comparison of macroeconomic performance and fiscal discipline in currency unions vs other SSA countries
- Early literature reported better real economic performance in the two CFA zones than the rest of SSA, but an overvaluation led to a large devaluation in 1994.
- Inflation rates in CFA zones have been unambiguously lower over the past 5 decades than in the rest of SSA (Masson and Pattillo, 2005, chapter 4).
- Competing views on whether monetary unions discipline fiscal policy:
  - Collier (1991): monetary union provides an “agency of restraint” for fiscal policy; French treasury enforcement was important for CFA.
  - Guillaume and Stasavage (2000): CFA central banks did not discipline fiscal policies because statutory limits were evaded.
  - Masson and Pattillo (2002): monetary union in ECOWAS would be insufficient by itself to exert fiscal discipline; needs regional surveillance institutions.
- Modeling (Debrun, Masson, and Pattillo, 2005; Masson and Pattillo, 2005) incorporates weakened ability of national fiscal policy to extract financing from the central bank in a regional context; these studies are relatively pessimistic about welfare gains from expanding unions beyond the CFA.

### Regional convergence as a precondition (or ongoing goal) for membership
- Convergence studies typically mirror EU criteria: convergence of inflation, reduction of public deficits and debt ratios, and sometimes per capita income proxies.
- Empirical findings on convergence:
  - Jenkins and Thomas (1996): SADC had not reached sufficient convergence for monetary union; Masson and Pattillo (2005) reached a similar conclusion later.
  - Agbeyegbe (2008): lack of convergence of nominal exchange rates and consumer prices among SADC countries.
  - Burgess (2009): except Zimbabwe, SADC countries had made solid progress in macroeconomic convergence.
  - Rossouw (2006): convergence should be viewed as a permanent goal rather than a precondition for membership (EU reference).
- West Africa experience:
  - WAEMU convergence after the 1994 devaluation was followed by relaxation and divergence (Doré and Masson, 2002).
  - WAMZ's convergence report (WAMZ, 2008) concluded “the pace of progress has been slow”; WAMZ postponement from 2009 to 2015 cited.

### Alternatives to traditional approaches: endogeneity, clustering, and trade effects
- Limitations of traditional approaches: multidimensionality, insufficiently dynamic criteria, and lack of institutional considerations (credibility anchors).
- Cluster analysis:
  - Bénassy-Quéré and Coupet (2005): CFA franc zone cannot be viewed as an OCA; WAEMU and CEMAC do not belong to the same cluster; WAMZ not supported by clustering.
  - Tsangarides and Qureshi (2008): CFA countries do not all belong to the same cluster; WAEMU and WAMZ display greatest dissimilarity; greater similarity between WAMZ and CEMAC possibly due to oil producers.
- Trade and endogeneity literature:
  - Rose (2000): monetary union may increase trade and reduce shock asymmetry.
  - Masson and Pattillo (2005): trade in African monetary unions about three times greater than without a shared currency (controlling for gravity factors), though debate remains about omitted features.
  - Tsangarides et al. (2006): monetary union increases intra-union trade by a factor of 1.7 in Africa, controlling for free trade agreements.
  - Tapsoba (2009): monetary integration increases trade intensity and business cycle synchronization, but less so in Africa than among industrial countries.
  - Masson (2008): even a doubling of intra-regional trade would not be sufficient to make most African monetary unions desirable in the DMP welfare model.
- Dynamic entry and integration path:
  - Yehoue (2005): trade externality endogeneity and thresholds imply the size and configuration of an existing union affect attractiveness; does not suggest convergence to a single African currency.

### Comprehensive framework: modeling strategy combining credibility and stabilization
- The model objective: incorporate effects of monetary integration on strategic interactions between monetary and fiscal authorities, capturing credibility and policy response to shocks.
- Rationale for model choice:
  - DSGE models lack flexibility for modeling strategic interactions and time-inconsistency across many heterogeneous low-income countries.
  - Barro-Gordon–type models allow simple intuition about strategic interactions and credibility, despite limitations in dynamics and micro foundations.
- The chosen model is a variant of Debrun, Masson, and Pattillo (2005) (DMP) incorporating:
  - Role of macroeconomic institutions in credibility for low inflation.
  - Financing of public expenditure via inflation tax vs other distortive taxes.
  - Role of monetary policy in output stabilization (OCA dimension).
- Model caveats:
  - Does not account for microeconomic gains from a common currency (reduced transaction costs, increased price transparency, competition, trade creation).
  - Welfare analysis is not explicitly micro-founded; results are suggestive but use plausible utility trade-offs.

### Model structure and equilibrium policies under autonomy
- Model setup:
  - Static, n-good, n-country region small relative to rest of world.
  - Open-economy Phillips curve with new-classical features (equation (1)): unexpected inflation raises output; distortive taxation reduces it; negative monetary spillovers proportional to trade intensity (ki, θ).
  - Fiscal instantaneous budget constraint: government expenditure must match revenue (equation (2)); includes propensity to spend on socially wasteful projects (i δ) and possibility of extracting resource rents (i ρ).
  - Authorities’ utility (equation (3)) dislikes deviations of public expenditure and inflation from targets (i g~ and i π~) and variability in distortive tax rates; output enters linearly (Barro-Gordon).
  - Inflation treated as a distortive tax; socially-optimal inflation rate is positive for positive target public spending.
- Equilibrium under monetary autonomy:
  - Time-consistent equilibrium policies exhibit an inflation bias (equation (7)) due to preference for stimulating output and public sector inefficiencies (i δ).
  - Inflation bias substitutes for costly turnover taxes and raises spending via seigniorage, but excessive inflation reduces welfare more than gains from higher spending.
  - Country-specific costs of a common monetary policy depend on imperfect shock correlation (OCA) and divergences in financing needs (FN = i i g~ + i ρ − i δ in text notation).

### Institutional change and gains from monetary unions
- Monetary union effects:
  - Participation centralizes monetary policy in a common central bank (CCB) that maximizes GDP-weighted sum of members’ utilities.
  - CCB faces steeper national Phillips curves by factor Σk∈M (1−θki) so a monetary impulse affects output less than national policy; this reduces average inflation bias.
  - Regional inflation reflects average financing need in the union (M A FN) rather than national FN.
- Implications:
  - Large group of high-inflation countries with strong trade linkages is more likely to form a mutually beneficial union than small group of low-inflation, limited-trade countries.
  - Heterogeneity in financing needs has ambiguous effects: it can hinder formation but also restrain fiscal excesses if low-FN partners discipline the union.
  - Feasibility risk if low-FN countries prefer national currencies when M A θ is too small to offset high-FN destabilizing influence.
  - Bargaining over a mutually beneficial CCB mandate could bias the CCB toward disciplined members; credible guarantees against interference are crucial.
- Central bank independence dimension:
  - Define central bank utility with political interference parameter i λ between 0 and 1:
    - i λ = 1: full political control; solutions equal national autonomy case.
    - i λ = 0: complete independence; eliminates Barro-Gordon bias but still accounts for government desire to finance wasteful spending.
  - Participation in union has same effect on Barro-Gordon bias as making national central bank independent under interference level M A θ λ = 1.
  - Supranational institutions (CCB) may be more credible than national reforms because treaties are harder to reverse and influence is harder to exert ex-ante.
  - Comparative attractiveness of union vs national independence shifts with countries’ capacity to enact credible national reforms.

### Status of monetary union projects in Africa (selected regions)
- Abuja Treaty roadmap targeted completion by approximately 2028; timetables are likely overly ambitious.
- East African Community (EAC)
  - Treaty (1999) roadmap: customs union → common market → monetary union → political federation.
  - Customs union launched in 2005 and to be fully fledged in 2010; Rwanda and Burundi joined in 2007.
  - Protocol for a 2012 common market signed November 2009; monetary union fast-tracked from 2015 to 2012 (decision August 2007).
  - Intra-regional trade: 17.5 percent of total exports and 7 percent of imports in 2007; Burundi and Rwanda source 20 percent of imports from EAC; over 20 percent of Kenya and Uganda’s exports go to EAC partners.
  - ECB and EAC central banks completed a preparedness study in January 2010 for an East African Monetary Institute and institutional frameworks.
  - Primary and secondary convergence criteria set for Stage 1 (2007–10) and Stage 2 (2011–12); inflation generally exceeded 5 percent ceiling; reserve cover targets mostly met; countercyclical fiscal policy led to misses in 2008/09.
  - Average correlations of terms of trade (1990–2007) higher than WAEMU or CMA but decreased in 2006–08.
- Southern African Development Community (SADC)
  - RISDP (2003) timetable: FTA by 2008, customs union by 2010, monetary union by 2016, single currency by 2018.
  - FTA launched August 2008; only part of 85 percent reduction of internal trade barriers achieved; overlapping memberships complicate integration.
  - SACU seen as potential anchor; SACU experiencing strains due to global crisis, sharp revenue declines; revenue-sharing formula pressures noted.
  - Intra-regional trade ~20 percent of total trade, but 5 percent if South Africa excluded.
  - Average correlations of terms of trade changes among member countries are quite low.
  - Convergence indicators focus on low inflation; only two countries met 10 percent inflation target in 2008; growth close to 7 percent in around one-third of countries.
  - Initiatives for institutional groundwork exist (Committee of Central Bank Governors); proposals for a common central bank for CMA discussed.
- ECOWAS / West African Monetary Zone (WAMZ)
  - WAMZ consists of non-WAEMU ECOWAS members (notably Nigeria, Ghana, the Gambia, Guinea, Sierra Leone) aiming to create a common currency and later merge with WAEMU.
  - WAMZ common currency launch postponed multiple times: initial target 2003 → July 2005 → December 2009 → postponed to 2015 (WAMZ heads of state, June 2009); ECOWAS currency target postponed to 2020.
  - Trade among WAMZ countries ~2 percent of total trade in 2007, much lower than WAEMU despite higher group GDP.
  - ECOWAS countries face asymmetric terms of trade shocks; WAMZ terms of trade correlations more negative in recent periods; WAEMU correlations higher.
  - WAMZ primary convergence criteria: single digit inflation; fiscal deficit to GDP (excluding grants) ≤ 4 percent; central bank financing of fiscal deficit as percent of prior year’s tax revenue ≤ 10 percent; gross international reserves ≥ 3 months of imports.
  - WAMI monitoring: only the Gambia met all four primary criteria for three years 2006–2008; Nigeria met four primary criteria for two years between 2006–2007 but only three in 2008; other members met fewer criteria.
  - Institutional progress: draft statutes for West African Financial Supervisory Authority, WAMZ payments system, Banking Statute prepared; Gambia, Guinea, Sierra Leone developing a joint payments system; efforts to integrate Nigeria and Ghana stock exchanges.
  - WAMZ is the most advanced in institutional, legal, and regulatory preparation among expansion/revival projects, though political commitment limited.

### State of fiscal and institutional convergence
- Fiscal indicators reviewed over 15 years: overall fiscal balance (including grants), level of public spending, and seigniorage (percent of GDP); analysis uses central government data and averages 1995–99 vs 2000–05.
- Empirical patterns:
  - Some fiscal convergence across SSA and sub-regions; exception: expenditure in the EAC essentially constant.
  - Convergence more evident within EAC and ECOWAS than across complete sample or within SADC (SADC appearance affected by Angola).
  - Fiscal convergence stronger for fiscal balance than for expenditure; seigniorage reliance declined markedly across SSA.
- Institutional quality indicators assessed: government effectiveness, control of corruption, voice and accountability — proxies for public spending inefficiency (i λ).
  - Evidence points to some convergence in institutional quality over the decade, but not consistently with absolute improvements; many countries show worsening institutional quality (below 45-degree line).
  - Only EAC exhibits across-the-board institutional improvements; control of corruption and democratic accountability do not show uniform convergence.
- Conclusions:
  - EAC and ECOWAS exhibit greater convergence and stronger convergence dynamics, increasing the likelihood that regional currency unions might be desirable for potential members.
  - Present and trend convergence indicators for a SADC-wide currency union are much less favorable.

### Application and next steps
- The paper proceeds to apply the DMP model with a new, more comprehensive and consistent calibration to analyze costs and benefits of creating or selectively expanding monetary unions in the SSA subregions studied.
- A dynamic general equilibrium model (Batte and others, 2009) applied to Nigeria and WAEMU provides preliminary results suggesting optimal policy regimes differ (e.g., Nigeria preferring a flexible exchange rate).

*Source: _wp10157 - conclusion for Eastern and Southern Africa, though they do find a few sub-regional*

### Section III. As described above, the model combines an emphasis on the role of fiscal

### _wp10157 - Section III. As described above, the model combines an emphasis on the role of fiscal

### Model structure, calibration, and key empirical equations
- Model combines:
  - emphasis on the role of fiscal discipline to provide an underpinning for low inflation; and
  - traditional OCA criteria of symmetry of shocks to evaluate gains and losses from monetary unions.
- Welfare:
  - measured in percent of GDP equivalents (scaled by country size);
  - assumed to depend positively on output growth and negatively on deviations from targets for inflation, tax revenues, and government spending (the latter two as ratios to GDP).
- Calibration:
  - parameters chosen to fit cross-country fiscal and institutional data over 1994–05, and the variance-covariance matrix of terms of trade and output over 1990–08.
  - recorded trade is scaled up by 25 percent to produce estimates of internalized trade (to account for under-recording of intraregional trade flows).
- Empirical implication summarized:
  - inflation (iπ) should depend on a country’s financing need (iFN), or, if a member of a monetary union, on the average FN of the union’s members (FNA). FNA is treated as a cross-sectional variable combining both possibilities.
  - the level for inflation (bias towards too expansionary monetary policy) will be reduced in a monetary union by the amount of intra‑union trade, captured by iA,θ.
  - tax revenues (rev) as ratios to GDP are explained by financing needs and the difference between a member’s FN and the union average; in a union tax revenues will also have to be higher to compensate for lower inflation bias.
- Estimated cross-section regressions (45 SSA countries, averages over 1994–2005). Results (standard errors in brackets) as presented in the source:

  iAii FNA ,577.0399.0812.2

   207.0
  2
  R

   (9.717)  (0.218)         (0.319)     p-value=0.0028

  and

  
  iAiiii
  FNAFNFNrev
  ,
  109.0137.0547.0173.1

   473.0
  2
  R

   (4.969)  (0.111)        (0.185)            (0.162)    p-value=0.0000

- Model uses variances of terms of trade shocks and of output and inflation to calibrate parameters capturing stabilization role of monetary policy and its effect on output.
- Appendix contains further parameterization details (not reproduced here).

### Main empirical findings and model implications
- Cross-sectional estimated relationships provide a reasonably good explanation of inflation and fiscal variables across Sub‑Saharan African countries, including those in monetary unions.
- Financing need has the expected positive effect on inflation and on tax revenues.
- Membership in a monetary union has the expected negative effect on inflation bias.
- Government tax revenues are well explained by financing needs and additional monetary union membership effects.
- The model’s utility-function parameters are calibrated using these estimates together with estimates of trade internalized in unions.

### Regional simulation results — welfare effects (selected findings)
- Approach:
  - Focused on proposed regional groupings (EAC, SADC, full ECOWAS, selective expansion of WAEMU).
  - Welfare changes reported in percent of GDP (welfare is expressed in percentage points of GDP).
  - Decompositions consider: monetary externality (credibility/internalization), fiscal asymmetry, and shock asymmetry.

- A. East African Community (EAC)
  - Table 6 notes limited high shock correlations (exception: Burundi–Uganda and Tanzania–Uganda).
  - Simulations (Table 7) — welfare gains/losses from an EAC monetary union among all five countries:
    - Burundi: Welfare Gain = 2.90 (Monetary Externality 0.81; Fiscal Asymmetry 2.36; Shock Asymmetry -0.20; GDP Share 1.87; Shock Correlation 0.17; FNA/FN 0.75)
    - Kenya: Welfare Gain = 1.40 (Monetary Externality 0.81; Fiscal Asymmetry 0.67; Shock Asymmetry -0.07; GDP Share 1.67; Shock Correlation 0.58; FNA/FN 0.92)
    - Rwanda: Welfare Gain = 0.64 (Monetary Externality 0.81; Fiscal Asymmetry 0.76; Shock Asymmetry -0.91; GDP Share 5.26; Shock Correlation 0.22; FNA/FN 0.91)
    - Tanzania: Welfare Gain = -0.30 (Monetary Externality 0.81; Fiscal Asymmetry -1.09; Shock Asymmetry -0.05; GDP Share 1.69; Shock Correlation 0.78; FNA/FN 1.17)
    - Uganda: Welfare Gain = 0.52 (Monetary Externality 0.81; Fiscal Asymmetry -0.16; Shock Asymmetry -0.14; GDP Share 9.51; Shock Correlation 0.62; FNA/FN 1.02)
  - Interpretation:
    - Significant improvement for Burundi and Kenya.
    - Rwanda and Uganda modest gains (less than 1 percent of GDP).
    - Tanzania small net loss, reflecting its better macroeconomic stability and a lower financing need.

- B. SADC
  - SADC is large and diverse; South Africa would likely dominate a SADC monetary union.
  - Table 8 highlights correlations of other countries’ terms of trade shocks with South Africa; some countries (including Namibia) have negative correlations.
  - Financing needs vary: Tanzania and most CMA members (except Lesotho) have low FNs; Angola, Lesotho, Zimbabwe have high FNs. Angola exhibits much higher standard deviation of terms of trade shocks.
  - Welfare calculations for a SADC monetary union including all countries (Table 9) are mixed:
    - Significant net gains mainly in more profligate countries that would gain from greater union-wide discipline.
    - Net losses for Angola and Mauritius (Angola: shock asymmetry; Mauritius: likely loss of credibility).
    - Tanzania would have a small net gain from joining SADC union because the union would be anchored by South Africa’s reasonable fiscal discipline.
    - Most other countries, including South Africa, record only modest net gains (less than half a percent of GDP).
  - A selective expansion of the CMA generally mutually beneficial (except for Angola and Mauritius).

- C. ECOWAS
  - ECOWAS composed of WAEMU (existing CFA franc zone) and WAMZ (remaining countries with a plan to create a union and then combine with WAEMU).
  - WAEMU countries have relatively more similar production structures and higher correlations of terms of trade; WAMZ countries have much lower correlations among themselves (and with WAEMU).
  - Nigeria’s terms of trade shocks are negatively correlated with neighbors: unweighted average correlation of -0.37 with WAEMU, -0.27 with other WAMZ countries.
  - Average financing need (FNA, GDP-weighted) — WAEMU = 38.5 percent of GDP; WAMZ = 33.4 percent of GDP. Within WAMZ: Nigeria = 31.5; Ghana = 45.8.
  - Full ECOWAS monetary union (Table 11) — welfare gains/losses:
    - Many members gain; only the Gambia is a net loser.
    - Two WAMZ countries reap net gains in excess of 2 percent of GDP.
    - WAEMU countries’ gains roughly 1 percent or less.
    - Nigeria would extract a small net gain despite ECOWAS average FN being higher than its own, reflecting the monetary externality and Nigeria’s dominant influence due to GDP weight.
  - Adding single countries to WAEMU (Table 12):
    - No WAMZ country would both increase its own welfare by joining and increase the welfare of all existing WAEMU members.
    - Gambia and Guinea would not gain from membership in these restricted unions.
    - Ghana and Sierra Leone would gain by joining WAEMU, but their large FN could lower existing WAEMU members’ welfare.
    - Nigeria’s membership would reduce welfare of existing largest WAEMU member, Cote D’Ivoire, because of output shock correlation changes.
    - The current composition of WAEMU is calculated to be an improvement over independent currencies; WAMZ is calculated to be worse than independent currencies for the Gambia and Guinea.

### Sensitivity analysis
- Parameters examined (mechanically halve or double in turn): a, b, c, , .
- Results (Table 13 summary):
  - Halving any parameter except c produces welfare gains qualitatively similar to the base case (both WAEMU and ECOWAS deemed welfare-improving for almost all members).
  - Doubling each parameter except a and  also has little effect.
  - Increasing a and  simultaneously:
    - increases the value of keeping inflation at target; and
    - makes the target more sensitive to terms-of-trade (output) shocks — making independent currency more valuable when shock asymmetries are present.
  - Lowering c (with others unchanged) makes monetary policy less effective in affecting output, requiring more active monetary policy and more inflation variation — again increasing the value of independent currency.
  - Parameters quantifying welfare effects of fiscal policy (b and ) have less impact on welfare comparisons for WAEMU/ECOWAS.

### Wider considerations beyond static simulations
- Two main limitations of simulations:
  - They give a static picture of unions likely to be sustainable given current macroeconomic and institutional convergence.
  - Simulations ignore the possibility of credible institutional reforms at the national level (medium-term fiscal frameworks, formal delegation to independent central banks with explicit mandates), because credibility of such reforms is judgmental and hard to measure objectively.
- Central bank independence:
  - Data suggest SSA central banks received greater legal independence since the end of the 1980s; indices comparable to the rest of the sample (Figure 9).
  - If legal independence reduces government influence (iλ goes down), the relative attractiveness of regional currency as a way to establish credibility could be reduced (marginal welfare gain from lower inflation decreases).
  - Domestic substitutes vs regional institutions:
    - Regional institutions might enjoy economies of scale from pooling human/financial resources and more credible guarantees against interference.
    - Central bank independence indices for regional banks (BEAC, BCEAO) are comparable to other SSA central banks, so the main argument for supranational credibility rests on greater difficulty for a single government to influence a supranational decision maker.
    - Supranational constraints can be reversed if member governments coordinate (example: EU Stability and Growth Pact suspension/weakening in November 2003).
- Regime for financial flows and external anchors:
  - Existing currency unions shaped by hard pegs and external guarantees (CFA–euro, French Treasury guarantee). Such a model seems hardly conceivable today for new unions.
  - For ECOWAS, extension of French Treasury guarantee to a wider union is doubtful; choice of new anchor and the consequences for WAEMU are key considerations.
- Financial stability and pooling of risks:
  - The global financial crisis highlighted benefits of pooled institutions for shock absorption, but direct impact on African countries was limited; transmission came via trade and terms of trade.
  - Importance of coordination of financial regulation and prudential supervision; mismatch between integrated financial area and fragmented supervision could expose unions to internal imbalances.

### Policy implications and recommendations (as discussed in the source)
- Monetary unions should be accompanied by:
  - enhanced regional surveillance of fiscal developments to minimize coordinated pressures on regional central banks by cash‑constrained governments.
- Institutional reforms at national level that could alter attractiveness of unions include:
  - adoption of medium-term fiscal frameworks with binding numerical constraints;
  - formal delegation of monetary policy to independent central banks with explicit mandates and guarantees against political interference.
- Cautionary notes:
  - The modest net gains found for many unions imply that monetary integration may not be particularly beneficial and depends critically on:
    - policy preferences regarding inflation vs output stabilization; and
    - effectiveness of monetary policy in affecting output.
  - Given limited and sometimes small net gains, careful assessment of institutional design and the feasibility of building credible supranational institutions is crucial before pursuing union formation or expansion.

### Conclusions and research agenda highlights
- Monetary integration remains an important policy issue in Africa; the paper integrates OCA criteria with fiscal financing needs, showing fiscal discipline is prerequisite for price stability and is a central challenge for unions.
- Main takeaways:
  - Despite large asymmetries of shocks and financing needs, gains from enhanced monetary stability can often offset costs from inability to stabilize idiosyncratic shocks — but net gains tend to be small.
  - Results are sensitive to assumptions about preferences and monetary policy effectiveness.
- Further research priorities identified:
  - develop cost-benefit assessments in models with richer dynamics and panel estimation;
  - account for dynamic adjustment of economic structures to a new regime (gains may materialize ex post);
  - better measure hard-to-observe variables (policymakers’ preferences, institutional quality, budgetary institutions effectiveness);
  - study political economy of building credible regional institutions versus strengthening domestic institutions;
  - examine implications of global financial crises and tail risks for union design; and
  - ensure financial integration is matched by integrated prudential supervision to avoid unsustainable internal imbalances.

*Italic line: Source: _wp10157 - Section III. As described above, the model combines an emphasis on the role of fiscal (PDF chapter/section).*

### Appendix 1. Calibration of the Model

### Appendix 1. Calibration of the Model

### Calibration steps
- The calibration involves four main steps:
  - 1) calculating the Financing Need (FN) variable, by regressing aggregate data for revenue and spending ratios on oil revenues, grants, and governance indicators;
  - 2) estimating the key parameters μ in the budget constraint;
  - 3) using the cross-section regressions of inflation and tax revenue on FN and the trade internalized in monetary unions to calculate utility function parameters a, b, γ;
  - 4) estimating the desired stabilization role for monetary policy (η) and the effect of monetary policy on output (c) from the variances of the residuals in the inflation and output equations.
- Cross-sectional data: averages for 1994–2005; number of Sub-Saharan African countries ranged from 29 to 45 depending on data availability.
- Variances for η and c were calculated using output and terms of trade data over 1990–08 for a more limited country set.

### Financing Need (FN): definition and estimation
- FN consists of:
  - society’s target for government spending g~;
  - a diversion wedge δ due to inefficient tax collection and wasteful spending that adds to financing without increasing welfare.
- Relationship used:
  - )(|)(| ~gidealgidealggFN
  - Simplified: )(| ~gidealgFN (A.1)
- Governance effects captured using ICRG indicators for 29 SSA countries (where available). Governance indicators: corruption (CO, 0–6), law and order (LO, 0–6), democratic accountability (DA, 0–6), bureaucratic quality (BQ, 0–4). Higher values indicate better governance.
- Revenues systematically depend on: per capita income (YPC, US dollars), the share of oil production in GDP (OilSh), and the ratio of grants to GDP.
- Three-stage least squares estimated a system of 3 equations—for revenues excluding grants (NR), grants (GR), and government expenditure (GOV). Variables and OilSh expressed as ratios to GDP. YPC2 is per capita income squared.
- Key qualitative estimation results (from Appendix Table 1 summary):
  - Revenues are positively related to per capita income but flatten with higher income, reaching a maximum at per capita income equal to $3300.
  - An additional percentage point of oil GDP increases the government revenue ratio by about one-quarter of that amount.
  - Better law and order and bureaucratic quality increase revenues.
  - Grants depend inversely on per capita income and positively on control over corruption.
  - Government spending increases one-for-one with non-grant revenues, but more than one-for-one with grants; spending decreases with a rise in democratic accountability.
- Normalization to SSA means: YPC = $1835 and OilSh = 7.39 per cent to calculate NRN, GOVN, and GRN (normalized values, including residuals).
- Ideal revenues set by further adjusting normalized values to ideal governance indicators (CO=6, LO=6, DA=6, BQ=4) using:
  - )6(435.1)4(868.1)6(252.1|COGRNBQLONRNideal (A.2)
- Financing need calculated as:
  - )()6(435.1)4(868.1)6(252.1
    |)(|
    GOVNGRNNRNGOVNCOGRNBQLONRN
    normalizedgidealFN
    
    
      (A.3)
- Appendix Table 2 provides country-level FN results (Averages, 1994-2005). Selected entries (exact figures preserved as in source):
  - Angola: Government Expenditure / GDP 52.74; Government Revenues Including Grants / GDP 41.97; Per Capita Income (US $) 8257.8
  - Benin: 18.91; 7.94; 3135.7
  - Botswana: 37.53; 9.83; 3942.2
  - Burkina Faso: 22.01; 8.52; 28139.5  [note: figures appear as in source table]
  - (Full country table provided in Appendix Table 2 of source.)

### Calibration of the model’s parameters: structural setup
- Equilibrium expressions for inflation πi and tax revenues τi (country i) are summarized by (A.4) and (A.5) (as in source), with:
  - Λ = bba 2)(
  - Distinction whether country i belongs to a monetary union M or not:
    - If in union: MA FN is GDP-weighted average FN in union; MA θ is trade internalized in union (ratio to GDP).
    - If not in union: i MA FN = FN_i and MA θ = 0 (second and fourth RHS terms in (A.5) zero).
- Parameters to calibrate: η, μ, γ, b, a, c.
  - a, b, γ: utility function parameters (weights on deviations from inflation, taxes, spending).
  - c: effect of inflation surprises on output.
  - μ: money income ratio (base for inflation tax).
  - η: reflects society’s desire for countercyclical policy.
- Error terms proportional to output shocks εi; MA ε is average shock in union or country’s own shock.

### 1. Estimating μ
- μ is taken equal to 0.376572, the broad-money-to-GDP ratio across SSA, averaged over 1994 to 2005. Countries weighted by GDP shares (omitting Eritrea and Sierra Leone for missing data).

### 2. Welfare function parameters (a, b, γ)
- Actual inflation defined as ppp/)(*100 1 and total revenues/GDP (rev) averaged over 1994–2005 used as dependent variables in cross-sectional regressions (A.4’) and (A.5’) to calibrate a, b, γ.
- MA θ measured as bilateral trade of currency union members (estimates from earlier work).
- Estimated SURE system coefficients show:
  - Financing need has a strong effect on revenues and inflation (significant at 10 percent level or better).
  - MA θ in inflation equation reduces inflation and is significant; its coefficient in revenue equation raises tax revenues but is not significant.
- Relationships to derive parameters as functions of coefficients and c, μ:
  - c b b a 3 1 
  - c b a b 3 1 
  - c ab a 23 1     
- Λ is proportional to c^2.

### 3. Stabilization role of monetary policy (η) and effect of monetary policy on output (c)
- η and c identified by variances of residuals in output and inflation equations, assuming output shocks Ai ε equal change in logs of TOT shocks scaled by openness.
- From (A.4) and (A.4’):
  - )()(
    )( 
    
    
    
    
    
    
    basdev
    sdev
    Ai
    i
    (A.6)
- η estimated as a GDP-weighted average of country-level η from (A.6) using 17 countries plus WAEMU and CEMAC (two composite currency regions). Excluded countries with major civil conflicts: Central African Republic, Democratic Republic of the Congo, Liberia, Mozambique, Sierra Leone, Sudan, and Zimbabwe.
- Parameter c calibrated by matching variance of TOT shocks with model-implied output equation variance. Output gap Gy_i measured as 100 times difference between log real GDP and trend; shocks ε equal 100 times change in log of terms of trade (1990–08).
- Variance expression leads to quadratic in c (A.8), rearranged to (A.9). Because a, b, γ, and Λ scale with c, coefficients in quadratic invariant to c; quadratic solved for c for each country; results averaged for estimate of c.
- Interpretation: estimates indicate monetary policy relatively ineffective: a one percent inflation surprise associated with a 0.6 percent change in output (approximate interpretation from calibrated c).

### Calibrated parameter estimates (summary table from source)
- Parameter estimates and standard errors (as reported):
  - c: 0.63735; Standard error 0.16294
  - μ: 0.37657; Standard error .. 
  - a: 1.20359; Standard error 1.7006
  - b: 2.33295; Standard error 3.2573
  - γ: 2.35337; Standard error 4.8626
  - η: 4.3213; Standard error 1.6642
- Estimator for FN/revenue/government equations: Three-stage least Squares. Selected regression significance notes (reported in Appendix Table 1):
  - Income per capita 0.01 *** ... -0.01 *** (t-statistics (2.75)(-3.67))
  - Income per capita squared (divided by 1,000,000) -1.52 ** ... 1.52 *** ((-1.91)(3.11))
  - Oil share in GDP 0.24 *** (4.22)
  - Bureaucratic quality 1.87 ** (1.32)
  - Grants coefficient 1.42 ** (2.55)
  - Corruption 1.43 ** (1.96)
  - Democratic accountability -0.93 (-1.54)
  - R squared: 0.74, 0.89, 0.41 for the three equations respectively
  - Number of observations: 29, 29, 29
  - Note: t-statistics in parentheses; superscripts *, **, *** denote significance at 10, 5, and 1 percent levels respectively.
- Appendix 1. Table 4: Calculation of η and c (selected country results; standard deviations over 1990-2008):
  - Angola: Inflation Residual 22.09; 1/TOT 7.79; Output Gap 8.4; 3/η 3.23; c 0.47
  - Botswana: 2.46; 1.69; 1.9; 1.65; 0.45
  - Ethiopia: 6.92; 1.52; 3.6; 5.19; 0.72
  - Ghana: 8.89; 2.34; 0.83; 4.32; 0.32
  - Nigeria: 12.2; 3.69; 4.8; 3.76; 0.53
  - South Africa: 2.11; 0.46; 1.64; 5.18; 0.75
  - WAEMU: 3.38; 1.13; 1.18; 3.41; 0.49
  - CEMAC: 5.3; 2.23; 2.43; 2.71; 0.58
  - Mean Estimate (weighted by GDP): 4/4.32/0.64
  - Standard Deviation (unweighted): 5/1.66/0.16
  - Notes:
    - 1/ 1995-2005.
    - 2/ The log change of the terms of trade, scaled by the average of imports plus exports over GDP.
    - 3/ Root mean square residuals of regression of 100*log(Y) on time.
    - 4/ Weighted by GDP.
    - 5/ Unweighted.

*Source: Appendix 1. Calibration of the Model (authors' estimates, as provided in the source PDF).*

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