Methodology: where these prices come from

What we collect and where it comes from

PlateCost runs on data from USDA AMS Market News. AMS analysts and market reporters gather price information directly from wholesale trades and publish it in standard reports. We don't survey anyone ourselves. We read what USDA already publishes.

We pull a curated set of series through USDA's MARS API:

• National shell eggs, weekly and daily reports
• The CME cash dairy weekly recap, which covers butter, cheese, nonfat dry milk, and dry whey
• Northeast fluid cream, from the regional cream report

That's the full list right now. We'd rather cover fewer series well than run a long list of pages nobody checks.

How the pipeline works

Each report cycle, our system calls the MARS API and pulls the latest observations for every series we track. Every observation gets stored with the report date it came from, not just the date we happened to fetch it. That distinction matters because USDA sometimes issues a report a day or two late, or revises a prior number.

When USDA issues a correction, we add it as a new record tied to the original report date. We don't overwrite the old value. If you look at the history on a series page, you can see both the original figure and the corrected one, each dated. This is the same approach USDA itself uses internally, and it means our numbers should always match what's in the official record, past and present.

Egg prices are a small wrinkle worth naming. USDA publishes national shell egg prices in cents per dozen. We convert to dollars per dozen before displaying them, since that's the unit people actually use when pricing a menu. The conversion is arithmetic only. We never adjust, smooth, or estimate a number that USDA didn't publish.

What shows up on a series page

Each series gets its own page built from this stored data. On it you'll find:

• The latest low, high, and average price from the most recent report
• A history of prior reports, so you can see the trend
• The name of the source report
• The date we last retrieved data for that page

That last point matters for a live data site. Reports come out on a schedule set by USDA, not by us. The retrieval date tells you exactly how current the numbers on the page are, so you're never guessing whether you're looking at last week's butter price or this week's.

What this is and isn't

Everything on PlateCost is a wholesale price. These are the prices reported at the level where large buyers and sellers trade, not the price you'd pay at a retail counter or see on a shelf tag. If you're comparing our numbers to a grocery receipt, expect a gap. That gap is normal and it's the reason wholesale data and retail data serve different purposes.

We also don't forecast. Every number on this site is something USDA already published. If a series page shows a trend line or a range, it's built entirely from historical AMS reports, not from any model of ours.

If you want the mechanism behind a specific number, check the source line at the bottom of that series page. It names the exact report and the retrieval date, so you can go verify it against USDA's own publication if you want to.

For background on how to read the numbers once you're on a series page, see how to read a price page.