8-over-8
Also known as: Eight-over-Eight
8-week avg / prior-year equivalent 8-week avg; year-over-year comparison.
8-over-8 is a year-over-year comparison metric that divides the current 8-week rolling average by the equivalent 8-week rolling average from the same period one year ago. It answers a simple question: is this service bigger or smaller than it was at this time last year?
Unlike raw attendance comparisons, 8-over-8 smooths out weekly noise on both sides of the equation. And unlike the Growth Index (which compares recent weeks to the trailing annual average), 8-over-8 compares apples to apples across calendar seasons — fall to fall, spring to spring.
Why it matters for your church: Seasonal patterns make raw year-over-year comparisons misleading. Summer attendance is always lower than fall, so comparing a July Sunday to a January Sunday tells you nothing. 8-over-8 neutralizes seasonality and gives you a clean, smoothed signal of whether you are gaining or losing ground relative to where you were twelve months ago.