Data Methodology and Corrections
Operator
ProteinPrices.com is operated by Chase Miller. Questions and correction reports sent to info@proteinprices.com go to a monitored inbox.
Collection and freshness
Product discovery and current product data come through Amazon's Creators API. Price feeds are scheduled twice daily. The timestamp shown on comparison pages is the newest feed timestamp; Amazon remains the final source of price and availability at checkout.
Comparable-product rule
A product enters the cost-per-protein ranking only when current price, servings per container, and labeled protein per serving are all present and within conservative plausibility bounds. Missing values remain missing; the site does not assign a typical scoop or serving value. New refreshes also retain extraction source/confidence metadata for auditing.
Formula
price ÷ (servings × protein grams per serving) gives cost per gram. The price index multiplies that result by 25.
Classification limitations
Categories and plant sources are assigned from conservative title keywords. A listing may fit more than one category, and ambiguous products remain unclassified. Rankings measure current price efficiency, not taste, ingredient quality, or health outcomes.
Corrections
To report an incorrect label value or product match, email info@proteinprices.com with the product URL or ASIN, the field in question, and a manufacturer label/source when available. Corrections are reviewed before becoming structured overrides.
Editorial and commercial policy
Comparison order is calculated from displayed data and is not changed for commission rate. The site earns from qualifying purchases, and commercial links are marked as sponsored. Educational copy is separate from the price-ranking formula.
Update log
- August 2026: added evidence-aware extraction, pre-publication quality gates, dedicated affiliate attribution, and current-market price benchmarks.
- August 2026: excluded incomplete nutrition rows from value rankings and tightened indexable brand thresholds.