A quick primer
The mechanics here are straightforward and backed by independent large-sample analysis. Fully pinning assets almost always drives an RSA to a "Poor" Ad Strength status, which in turn reduces impression volume for the fully pinned RSA compared to other ads in the same group that pin less aggressively. Every pinned position cuts into the number of combinations the system can assemble and test: pinning just two headlines has been shown to cut the system's testing potential by roughly 99.5% — a sharp, nonlinear effect even from a small number of pinned positions.
Industry observation draws a direct line between Ad Strength and reach: pinning assets lowers Ad Strength, and Ad Strength broadly correlates with likely impression volume — which is why pinning should be applied selectively if you want to preserve steady traffic. The logic makes sense: the fewer variable combinations available to a pinned ad, the fewer chances Google Ads has to assemble the most relevant pairing for each specific query — while an unmodified (fully free) ad in the same group can flex to match a wider range of queries, earning more opportunities to show as a result.
What to check before you touch anything
- How many positions are pinned in the lower-reach ad — a single pin and a fully pinned ad have very different effects on reach.
- How much Ad Strength differs between the pinned and unpinned ad in the same group — a sharp gap (say, Poor versus Excellent) directly explains the impression gap.
- Whether the pinned positions each carry a single variant of text instead of several — pinning one single variant per position maximizes the restriction on testing; pinning several unique variants to the same position partially preserves rotation.
- Whether there was a deliberate reason for full pinning (legal, regulatory, brand requirements) or whether it accumulated over time through edits without ever being revisited.
- Whether the traffic volume the pinned ad receives is acceptable relative to business goals — sometimes a smaller but more predictable, fully controlled reach is a deliberate, reasonable trade-off rather than a problem.
Possible approaches
- If pinning is excessive (many positions pinned with no clear justification) — release the pins that aren't genuinely necessary, keeping locked only what actually needs it.
- If pinning is genuinely necessary (regulatory requirements, a mandatory brand message) — pin several unique wording variants to the same position rather than a single one, which partly restores testing room and reduces the reach hit.
- If the reduced reach is an expected and acceptable consequence of a deliberate decision to control the copy — don't try to "fix" it through Ad Strength workarounds; the trade-off between control and reach is objective and unavoidable in that case.
- If the ad was set up fully pinned "by default" without a genuine need for that level of control — reconsider the approach and move toward a more flexible structure, closer to the unpinned variant's level of pinning.