Fallback CTR prior
also called Generic priorFallback curve
Definition
The generic position-to-click-rate table used only when no curve can be fitted from the site's own data, so a worklist can still be sized, labelled in the output as not this site's curve.
Scope, grain and dimensions
- Grain
- One position, globally.
- Dimensions
- position
- Aggregation
- A lookup by rounded position, clamped to positions 1 through 20. It is not fitted and does not vary by segment cell.
- Metric type
- rate · expected share of impressions that clicked, per position (0 to 1)
Data sources
Where you'll see this
Named reports that normally include this metric.
Content decay reportCTR opportunity reportSearch opportunity report
Skills and analyses that use it
Skills carry the judgment; the analysis verbs do the reading.
Skills
Analysis verbs
striking_distance
Method rungs and levers
A rung tells you what a movement here can and cannot explain, read the rungs below it first.
levers L3 Refresh & content quality
Ask Quattr
- "What happens when there is not enough data to fit our own CTR curve?" Simulate this →
- "Why is this worklist marked as using a fallback?" Simulate this →
Caveats, freshness and failure modes
It fires only when the site's own fit fails; every affected row is marked, and the response carries an explicit fallback warning.
Any upside sized from it is not this site's modeled upside, and the difference is not a rounding matter.
The rest of this product line refuses published click-rate tables on the grounds that they do not describe today's results pages, which makes the presence of this one a contradiction to resolve, not a convenience to document.
- Freshness
- 1 to 2 days behind, Google's own reporting lag. Any answer touching the last 48 hours says so on the card.
Common failure modes
- Presenting fallback-sized upside as the site's own modeled upside.
- Comparing a fallback-sized worklist to a fitted one across periods.
Related metrics and workflows
Verification
A definition is the smallest part of this.
The measurement matters because something acts on it. Here is the rest of the showcase, in the order most people find useful.