A quick primer
An across-the-board, simultaneous drop in performance for every keyword in a campaign is an important diagnostic signal on its own: if the cause were local (say, individual keywords became less relevant, or ran into heightened competition specifically on those terms), the drop would be uneven. A synchronized, simultaneous drop across the whole campaign points to a shared, systemic cause operating at the campaign level all at once, rather than at the level of individual keywords. Combined with a "Bid strategy constrained by target" status, this is especially telling, since that status already indicates the target is an active limiting factor; the question is whether the target actually caused the drop, or whether the drop happened for another reason and simply coincided in time with an already-existing constraint status.
The most likely systemic causes of an across-the-board drop are: (1) a sharp, one-time change to the target itself (say, an automated rule or a person lowered tCPA/tROAS for the whole campaign at once); (2) a change in how conversion data is being passed at the campaign-wide level (a tag failure, a change to the conversion window, a change in attribution), causing the system to see fewer conversions, or a distorted value for them, across all keywords at once; (3) an outside event affecting the whole auction in that niche equally (a seasonal shift, a major industry event, a broad change in competitor activity). The official breakdown of how conversion tracking settings affect the data the bid strategy sees is in Google Ads Help's article on setting up conversion tracking, and an overview of the logic behind the status itself is in Google Ads Help's article on bid strategy statuses.
What to check before you touch anything
- The campaign's and account's Change History — was the target, a conversion action, the conversion window, or attribution changed around the time the across-the-board drop started?
- Is the conversion tag technically working correctly? Check via a tag debugger, and cross-reference the count and total value of Google Ads conversions against your actual CRM/platform data over the last few days.
- The structure of the search terms report over comparable half-periods — did performance drop for the same search terms that were already driving traffic, or did the makeup of the queries change (a growing share of new, lower-quality phrasing crowding out previously effective terms)? These are two different diagnoses: in the first case, the underlying demand or offer is genuinely underperforming; in the second, the problem isn't "performance" at all — it's a shifted query mix, which calls for negative keywords and tighter match types, not a target change.
- The search results themselves, manually — has a competitor launched a new landing page with new messaging or an offer that's objectively started pulling clicks and conversions away from you?
- Competitors' ad libraries on social platforms (Meta Ad Library, TikTok Ads Library, Reddit Ads) — has a competitor launched an aggressive campaign flight on other channels that's simultaneously boosting their brand awareness and indirectly strengthening the competitiveness of their Google Ads presence too, even if you're only directly competing in Search.
- What does Auction Insights show for your core keywords over the same period — did competitor activity rise synchronously across the whole niche, rather than on individual terms?
- Are there outside industry or seasonal factors that could explain a simultaneous shift in user behavior across the whole keyword set?
Possible approaches
- If Change History shows the target was changed around the time the drop started, first assess whether that change was deliberate and well-founded, and, if needed, revert the target as a control check.
- If a technical problem with conversion reporting is found, fix that first; once it's fixed, the "constrained by target" status and the observed performance drop may turn out to be a consequence of distorted data rather than a genuine problem with the target or the keywords themselves.
- If the search-term analysis shows the issue is a shift in query mix (a growing share of low-quality terms, rather than a drop in the performance of previously effective ones), the fix is targeted: tighten negative keywords and match types, rather than revisiting the whole campaign's target.
- If checking the search results and social ad libraries shows a competitor launched genuinely stronger messaging and is simultaneously stepping up presence on other channels, the drop is probably explained by a real rise in their competitiveness, and the fix should be sought in revisiting your own offer and messaging, not just in Google Ads settings.
- If the drop is explained by an outside, industry-wide factor (rising competition across the whole niche, seasonality), targeted work on individual keywords is unlikely to fix much — it's more logical to consider revisiting the target itself given the changed market conditions.
- Either way, don't jump straight to interpreting an across-the-board drop as a signal to loosen the target — if the real cause is in the data, the query mix, or an outside factor, loosening the target won't solve the problem, it'll just temporarily mask it with higher spend.
- Telling apart a genuine systemic cause from a coincidence by manually checking Change History, the tag's technical status, search-term structure, the search results, and competitor ad libraries across multiple channels is a labor-intensive, multi-part diagnostic process. Our tool (DataMind) cross-references performance trends across a campaign's entire keyword set simultaneously, including a breakdown of search-term structure, and clearly indicates whether a drop is synchronized (pointing to a shared cause) or localized to part of the keywords, which immediately narrows down the list of likely causes.