Comparison
Two opponent-adjusted ways of saying how good an NFL team was. This page explains what each one measures, how they differ, and which questions each is the wrong tool for.
DELTA is ykb.football's team-season grade. It rates a completed season on a 0–10 scale anchored to every team season since 2005, and grades each unit inside that season separately, so a team can be a 7 overall while its run defense is a 3. It is free to read and needs no account.
DVOA — Defense-adjusted Value Over Average — is a play-by-play rating created by Aaron Schatz. It compares each play to a league-average baseline for that situation and expresses the result as a percentage above or below average. It was published for years at Football Outsiders and now lives at FTN Fantasy, behind a subscription.
Both adjust for the quality of the opposition faced, which is what separates either one from raw yardage or points. They are independent measures, not versions of each other, and neither is derived from the other.
| DELTA | DVOA | |
|---|---|---|
| What it rates | A team season, plus each unit inside it (offense, defense, special teams, and the pass/rush split of each). | Team, unit and player performance, built up from individual plays. |
| Opponent adjustment | Yes — production is weighed against the quality of the units actually faced. | Yes — opponent adjustment is the "defense-adjusted" in the name. |
| Time grain | Season only. There is no weekly or in-season DELTA. | Updated through the season, including weekly figures. |
| Scale | 0–10, fixed to every team season since 2005. 5 is an average team season; most units land between 3 and 7. | A percentage above or below a league-average baseline, where 0% is average. |
| Reads across years | Directly. The scale is anchored to the whole 2005-onward history rather than re-scaled each season. | Published with era adjustments; check FTN for how a given table is baselined. |
| Coverage | 2005 to the most recent completed season. | Back to 1978, per FTN. |
| Access | Free to read, no account required. Every team page is public and crawlable. | An FTN subscription. |
| Published by | ykb.football — built from public play-by-play data. | FTN Fantasy. DVOA was created by Aaron Schatz and published for years at Football Outsiders. |
No. They are separate ratings from different publishers, built independently. Both are opponent-adjusted measures of NFL team strength, so they tend to agree about who was good, but they are computed differently and are read on different scales — DELTA on a fixed 0–10 scale, DVOA as a percentage against a league-average baseline. Neither reproduces the other.
Yes. ykb.football publishes DELTA free and without an account: an opponent-adjusted grade for every team season since 2005, broken out by offense, defense and special teams, and by the pass and rush split within each. DVOA itself requires an FTN subscription.
Yes. A unit is weighed against the quality of the units it actually faced, so a hard schedule is not held against a team and an easy one does not flatter it. Two teams with identical raw production can land on different DELTA grades for that reason alone.
Every team season from 2005 through the most recent completed season. DVOA goes back further — to 1978, per FTN — so for seasons before 2005 DELTA has nothing to offer.
No. DELTA is a season-level grade and is only meaningful over a full season, so it cannot answer "who is the best team right now" in Week 8. That is a real limitation against in-season ratings like DVOA. For a single game, use the box score and the team efficiency stats instead.
It is a clearly above-average unit. The scale is anchored to every team season since 2005: 10 is the best unit of the last two decades, 0 the worst, and 5 a comfortably average team season. Most units land between 3 and 7, so a 7 sits near the top of the common range.
Every team season since 2005 is public. Start at the team directory for the current season and open any team for its unit grades, or read the full definition in the metrics dictionary.