Potatoes: Correlation
Prices it moves with, and why
Potato prices are local and volatile, depending on harvests, storage stocks and weather. The series is a US russet potato index. India and China are the largest growers, and their markets are only loosely tied to it.
Price index US producer price index: russet potatoes index, BLS base period · monthly, Jan 2006 to Sep 2026What its price moves with
Selected linkPotatoes and Starch and cellulose derivatives
Monthly changes 0.07 little or none correlation 12-month changes 0.20 little or none correlation Last 5 years 0.03 monthly changes Lead or lag −6 mo Potatoes tends to lead by 6 months (r 0.14) Price function, Jan 2006 to Sep 2026 Potatoes ≈ 7.90 × (Starch and cellulose derivatives)0.55 R² 0.13 On this fit, a 10% higher starch and cellulose derivatives price goes with a 5.4% higher potatoes price over the long run. Units: index, BLS base period and index (BLS base period =100). The fit is loose, so treat the function as a rough guide.Chart: Potatoes and Starch and cellulose derivatives prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Potatoes price against Starch and cellulose derivatives price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.Potatoes are processed into starch for food, paper and textiles, competing with maize and cassava starch. The starch index is mainly maize wet milling, and shows little link with potatoes: monthly moves correlate at 0.07 and yearly moves at 0.20.
little or none co-movement month to month · 249 months Show chartsPotatoes need a lot of potassium, so potash is a major fertiliser cost. The link with potato prices is weak: monthly moves correlate at 0.09 and yearly moves at 0.32.
little or none co-movement month to month · 249 months Show chartsLate blight can destroy potato crops, so growers spray fungicides many times a season. The US pesticides index correlates with the potato index at 0.10 for monthly moves and 0.42 for yearly moves, partly a shared US farm cost cycle.
little or none co-movement month to month · 249 months Show chartsDiesel for machines and power for cold storage are large costs for potatoes, which are bulky and perishable. The diesel proxy shows little link: monthly moves correlate at 0.02 and yearly moves at 0.23.
little or none co-movement month to month · 249 months Show chartsPotatoes and wheat are both staple foods, and in poor potato years buyers switch to grains. Monthly moves correlate at 0.03 and yearly moves at 0.35, since potatoes trade in local markets.
little or none co-movement month to month · 249 months Show chartsHow to read these numbers
Correlation of monthly changes (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak.
12-month changes compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs.
Price function is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation.
Lead or lag checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months.
Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link.
Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site.