Data sources

Source status

Method

• Decomposition: the Christiano–Fitzgerald asymmetric band-pass filter (random-walk assumption, drift removed; the same formula as statsmodels' cffilter) applied to log real prices. Trend = movements longer than 70 years; supercycle = 20–70 years; the rest = shorter swings. Values shown as % above or below trend.
• Waves: a rising phase runs from the lowest point of the component before it turns positive (trough) to its highest point (peak); the next trough is the lowest point before it turns positive again.
• Co-movement test: the average of the pairwise correlations between the supercycle components of the 42 commodities with data from 1900. Fake prices: each commodity's annual log changes shuffled at random and cumulated (500 runs), which keeps their size and drift but removes any link between commodities.
• Deflator test: the same test for 1960 onwards, on commodities that appear in both Jacks and the World Bank data, using the World Bank's MUV-deflated real prices.
• Monthly real prices: World Bank nominal monthly prices divided by US CPI and expressed in dollars of the latest month.
• Limits: only four waves since 1900; the band is a convention; the end of the filter is revised as data arrives; the index weights (1975 production values) give energy a large role. See the list on the "Were they real?" page.

Studies referred to

• Jacks, D.S. (2019), "From Boom to Bust: A Typology of Real Commodity Prices in the Long Run." Cliometrica 13(2) (data: real prices 1850–2025)
• Jacks, D.S. (2026), "Chartbook of Real Commodity Prices, 1850-2025"
• Erten, B. & Ocampo, J.A. (2013), "Super Cycles of Commodity Prices Since the Mid-Nineteenth Century." World Development 44 (UN working paper version)
• Cuddington, J. & Jerrett, D. (2008), "Super Cycles in Real Metals Prices?" IMF Staff Papers 55(4)
• Heap, A. (2005), "China: The Engine of a Commodities Super Cycle." Citigroup (as summarised in Erten & Ocampo 2013)
• Christiano, L. & Fitzgerald, T. (2003), "The Band Pass Filter." International Economic Review 44(2)
• World Bank, Commodity Markets Outlook (October 2018), special focus "The Changing of the Guard: Shifts in Commodity Demand"
• IEA (2021), "The Role of Critical Minerals in Clean Energy Transitions": 16.5 years on average from discovery to first production
• Federal Reserve History, "Oil Shock of 1973–74"
• Federal Reserve History, "Oil Shock of 1978–79"

Updates

The data is fetched and the site rebuilt every Monday morning (Japan time). The World Bank updates its prices at the start of each month and Jacks updates his data once a year. The text on the causes of each wave is revised by hand.

Operator

• Operator: After Deal operator (an individual)
• No connection with any organisation, including the operator's employer, and none of its work product or data is used.
• Nothing on this site is investment advice. Data belongs to each publisher and may contain errors or delays.

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