## CHAPTER 1 — Online Annex (Online Table 1.SF.1 Statistical Properties of Real Commodity Prices)

## Source details

**Canonical URL:** [CHAPTER 1 — Online Annex (Online Table 1.SF.1 Statistical Properties of Real Commodity Prices)](https://www.imf.org/-/media/files/publications/weo/2019/april/english/ch1annex.pdf)

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### Table scope and column definitions
- Coverage: Statistical properties of real commodity prices for a wide range of commodities (ENERGY; NON-ENERGY: Agriculture, Food, Fertilizers, Metals, Precious Metals).
- Period columns: Start Date; End Date.
- Statistical columns: Average Amplitude of Contraction; Average Amplitude of Expansion; Average Duration of Contraction; Average Duration of Expansion; Number of Contractions; Number of Expansions; Average Sharpness of Contraction; Average Sharpness of Expansion.

### Selected commodity statistics (exact values as reported)
- Coal, Australia (1979m1–2018m11)
  - Average Amplitude of Contraction: -0.71
  - Average Amplitude of Expansion: 0.68
  - Average Duration of Contraction: -36.75
  - Average Duration of Expansion: 26.71
  - Number of Contractions: 7
  - Number of Expansions: 8
  - Average Sharpness of Contraction: -0.02
  - Average Sharpness of Expansion: 0.03
- Coal, South Africa (1990m1–2018m11)
  - Average Amplitude of Contraction: -0.76
  - Average Amplitude of Expansion: 0.78
  - Average Duration of Contraction: -45.40
  - Average Duration of Expansion: 24.40
  - Number of Contractions: 5
  - Number of Expansions: 5
  - Average Sharpness of Contraction: -0.02
  - Average Sharpness of Expansion: 0.03
- Crude Oil — Brent (1957m1–2018m11)
  - Average Amplitude of Contraction: -0.79
  - Average Amplitude of Expansion: 0.85
  - Average Duration of Contraction: -41.40
  - Average Duration of Expansion: 30.09
  - Number of Contractions: 11
  - Number of Expansions: 10
  - Average Sharpness of Contraction: -0.02
  - Average Sharpness of Expansion: 0.03
- Crude Oil — WTI (1957m1–2018m11)
  - Average Amplitude of Contraction: -0.73
  - Average Amplitude of Expansion: 0.77
  - Average Duration of Contraction: -44.70
  - Average Duration of Expansion: 29.80
  - Number of Contractions: 10
  - Number of Expansions: 10
  - Average Sharpness of Contraction: -0.02
  - Average Sharpness of Expansion: 0.03
- Natural Gas, US (1991m1–2018m11)
  - Average Amplitude of Contraction: -1.07
  - Average Amplitude of Expansion: 1.05
  - Average Duration of Contraction: -26.67
  - Average Duration of Expansion: 25.29
  - Number of Contractions: 7
  - Number of Expansions: 6
  - Average Sharpness of Contraction: -0.04
  - Average Sharpness of Expansion: 0.04
- Sugar, World (1957m1–2018m11)
  - Average Amplitude of Contraction: -1.47
  - Average Amplitude of Expansion: 1.44
  - Average Duration of Contraction: -4 3.44 39.33
  - Number of Contractions: 9
  - Number of Expansions: 9
  - Average Sharpness of Contraction: -0.03
  - Average Sharpness of Expansion: 0.04
- Copper (1957m1–2018m11)
  - Average Amplitude of Contraction: -0.81
  - Average Amplitude of Expansion: 0.79
  - Average Duration of Contraction: -45.89
  - Average Duration of Expansion: 36.89
  - Number of Contractions: 9
  - Number of Expansions: 9
  - Average Sharpness of Contraction: -0.02
  - Average Sharpness of Expansion: 0.02
- Iron Ore (1975m1–2018m11)
  - Average Amplitude of Contraction: -0.47
  - Average Amplitude of Expansion: 0.57
  - Average Duration of Contraction: -47.43
  - Average Duration of Expansion: 24.63
  - Number of Contractions: 8
  - Number of Expansions: 7
  - Average Sharpness of Contraction: -0.01
  - Average Sharpness of Expansion: 0.02
- Gold (1964m1–2018m11)
  - Average Amplitude of Contraction: -0.63
  - Average Amplitude of Expansion: 0.77
  - Average Duration of Contraction: -51.57
  - Average Duration of Expansion: 42.86
  - Number of Contractions: 7
  - Number of Expansions: 7
  - Average Sharpness of Contraction: -0.01
  - Average Sharpness of Expansion: 0.02
- Palladium (1987m1–2018m11)
  - Average Amplitude of Contraction: -0.93
  - Average Amplitude of Expansion: 1.40
  - Average Duration of Contraction: -47.50
  - Average Duration of Expansion: 48.75
  - Number of Contractions: 4
  - Number of Expansions: 4
  - Average Sharpness of Contraction: -0.03
  - Average Sharpness of Expansion: 0.03

### Methodology and sources (exact reporting)
- Sources: IMF, Primary Commodity Price System; and IMF staff calculations.
- Peak and trough detection: Peaks and troughs are determined according to the Harding and Pagan (2002) algorithm.
- Window and cycle parameters: Window and minimum phase and minimum cycle length set at 3, 12, and 24 months, respectively.

*Source: COMMODITY SPECIAL FEATURE — Online Annex, Online Table 1.SF.1 Statistical Properties of Real Commodity Prices (International Monetary Fund, April 2019).*

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_Source: https://www.imf.org/-/media/files/publications/weo/2019/april/english/ch1annex.pdf_