Video completion rate (VCR)

Amazon's unified-reporting definition is complete views (video) divided by starts (video), the top of a quartile ladder — 25%, 50%, 75%, complete — counted with rewind de-duplication, so a viewer who scrubs back is scored on the total percentage of unduplicated video viewed rather than on replayed seconds. The start count exists only on the Amazon DSP side: videoAdStart and videoAdCompletionRate live on the dspCampaign, dspInventory, dspTech, dspGeo and dspAudience report types. Sponsored Brands, Sponsored Display, Sponsored TV and the Sponsored Products video ad extension get quartile columns defined as the number of impressions where the video was viewed to 25%, 50%, 75% or 100% — no start column, no completion-rate column. Their only video rate is the 5-second view rate, on Sponsored Brands and Sponsored Products video.

A VCR calculated on Sponsored Brands or Sponsored TV is really completes over impressions — structurally lower, and not comparable to a DSP VCR. Label the denominator; never stack the two in one column. Sponsored ads do get one true completion rate: completionRateVideoAd in the benchmarks reports, with P25/P50/P75 peer percentiles at brand-and-category grain — a sanity check, not a per-campaign lever. Read the curve, not the endpoint: the 25%–50% drop diagnoses the hook, the 75%–100% step mostly reflects placement and format, and near-total completion on a six-second bumper is arithmetic. Completion is not viewability — a video can play to the end and fail the MRC bar of 50% of pixels in view for two continuous seconds, so never report VCR as attention without pairing it to viewable impressions.