The cumulative data-retention success rate over the selected window for this provider and probe location, shown with its 95% confidence interval (CI). Each point is the running share of proving periods that were proven (not faulted) up to that day; the shaded band is the Wilson score interval for that rate. Retention is reported as cumulative proving-period counters, so the daily counts are derived from per-poll deltas.
The band starts wide and narrows as periods accumulate. Once it sits entirely above (or below) the 99.8% approval threshold (the dashed line is equivalent to ≤ 0.2% faulted), the provider is statistically distinguishable from the threshold, which can happen well before any fixed sample target is reached. The dashed line on the right axis tracks the cumulative number of proving periods the rate is based on.
Caveat: the confidence interval assumes independent trials, but retention faults tend to cluster. This means a single outage faults many consecutive periods at once. The effective sample size is therefore smaller than the raw period count, so the band is somewhat optimistically narrow and should not be read as exact at the boundary.
For more information about the storage proving probes, see Data Retention.
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