Methodology

How the data is collected

Everything on this site comes off the USDA Agricultural Marketing Service reporting API, pulled on a fixed schedule. Four report families: the shipping point (FOB) reports that price potatoes at the origin district, the movement reports that carry shipped and border-crossing volumes, the terminal-market reports, and the national retail-ad report. There is no scraping and no estimation; every figure comes straight off a structured USDA report row, and the pack, variety, grade, size and cultivar on every row are mapped to a fixed vocabulary. A description that does not map is logged and skipped, never guessed, because one 50 lb carton price read as a sack price is a wrong number to a buyer.

Each pull covers a trailing window, not just the newest day, and a missed or partial run backfills on the next one. Nothing is silently skipped or left blank.

The price range, and why there is no single number

USDA quotes a low-high range for each origin, pack, grade and size, and often a narrower mostly range covering where most of the day's sales landed. We store the whole range and chart it as the shaded band on every FOB page: the mostly range where USDA gives one, the low-high range where it does not. A midpoint line is drawn through the band only so the chart and the week-over-week math have a single value to track. That midpoint is never quoted as a price. Everywhere a price appears in words, it appears the way USDA published it: "mostly $11.00-12.00, 50 lb carton."

Carton counts and the per-cwt board

A 50 lb russet carton is size-graded by count, and a district can quote every count from 40 to 100 on the same day, so each count keeps its own price series; collapsing them would throw away the size spread the market trades on. Round reds, whites and yellows carry a Size A or Size B grade instead. Because packs are priced on different weights, a 50 lb carton and sack per package, a bulk tote per hundredweight, we also carry every price divided to a per-cwt figure using the weight the quote is actually priced against. That is deterministic arithmetic on a published price, not an estimate, and it is what lets a carton, a sack and a baled bag share one board.

Cultivar, grade and appearance keep their own series

Where a district quotes Russet Norkotah and Russet Burbank the same day at different prices, each cultivar keeps its own series so the premium is never averaged away. The same rule holds for a US No. 2 quote against a US No. 1, and for an appearance premium against a base lot. No published quote overwrites another.

How districts roll up to an origin

USDA prices potatoes by district, and one growing origin can span two of them. Each district keeps its own price series, because two districts of one origin can quote on the same day and must not overwrite each other. An origin page features its headline district, the one with the most quotes, as the shaded band, and draws any sibling district that quotes the same pack and size as its own line. The prices are never averaged into a synthetic origin number.

Sizeless and originless quotes are kept, not dropped

Specialty packs are routinely quoted with no size stated, and locally repacked terminal lots carry no origin at all. Rather than guess a size or an origin, or silently drop the quote, we keep each as its own clearly labeled series. A quote with no size can never contaminate a sized one, and the label says plainly that the field was absent in the source.

Movement, in hundredweight

Movement is the volume shipped, reported separately from price and carried here in hundredweight, the unit the potato trade counts in, summed across the districts and modes USDA lists for an origin and day. On an import page the movement is the volume crossing from Canada. Summing published volumes is deterministic; the split by crossing and mode rides underneath.

How comparisons are computed

Each comparison pairs the latest reading with an earlier one on the same series. Week over week reaches back about seven days, month over month about thirty, and year over year about a year. USDA does not quote every district every day, so we do not require a reading on the exact calendar day: we take the nearest real quote inside a short window around the target, a few days for the weekly comparison, about a week for the monthly, and about two weeks for the yearly. When no actual quote falls inside that window, the comparison is left off rather than forced onto a date that does not fit, so a gap in reporting never produces a made-up move.

The five-year comparison lines the current reading up against the same time of year in earlier years. For each prior year that has data, up to five, we take the quote nearest the same calendar date, within about a week and a half, and compare the current reading to the median of those readings. Median, not average, so one freak year does not skew the baseline. A series needs at least two earlier years before the comparison appears, and the label always names the number of years actually used, so a young series reads "vs 3-yr median" instead of claiming a five-year history it does not have.

Direction is neutral

Every reader of this site is on one side of the trade or the other, so a price move here is not good or bad the way a shortage or a surplus is. The colored tags on the scoreboard mark how far a reading sits from its own five-year normal, in either direction, not whether that is welcome. A move up helps sellers and costs buyers, and the reverse; we report the direction and the size, and leave the judgment to the reader.

What we do not compute

We do not forecast anything. We do not model crop transitions, freight, or the next week's quote. Where a public number does not exist, or a district is simply not quoting, the site says so rather than substituting an estimate.

For the plain-English version of how to read a page once the numbers are in front of you, see how to read this.