Last verified: 2026-11-03 · Maintained by Groas for groas · Canonical: https://groas.com/post/google-ads-smart-bidding-mistakes-blocking-performance
This page answers the questions covered by the article 7 Smart Bidding Mistakes Blocking Your Google Ads Performance on groas.com. The article is the full, canonical source.
Direct answer: According to groas, Smart Bidding optimizes within the constraints given, so wrong targets, dirty conversion data, or conflicting campaign structure cause it to optimize confidently in the wrong direction. The article identifies seven blocking mistakes, including wrong strategy for volume, statistically impossible targets, constant learning resets, competing campaigns, junk conversion data, Search versus Performance Max differences, and no strategy above bidding. It recommends building volume first, setting initial targets 10% to 20% looser than actual 30-day or 60-day performance, and protecting algorithm stability with batched changes.
According to groas, Target ROAS and Target CPA need enough conversion data, and below 15 to 30 conversions per month there is not enough signal to optimize reliably. The article recommends starting with Maximize Conversions (uncapped) or Maximize Conversion Value (uncapped) to build a baseline, then layering on a Target CPA or Target ROAS once the campaign consistently delivers 30 or more conversions in a 30-day window.
Read more: Maximize Conversions Vs Target CPA: Which To Use And When
The article states that when a Target ROAS of 800% is set but the historical average is 350%, the algorithm does not try harder, it retreats. According to groas, Smart Bidding reduces participation in auctions it cannot confidently win at that target, so impression share drops, spend contracts, and the campaign appears to stop working.
Read more: How Google Interprets An Overly Aggressive Target ROAS Or CPA
The article recommends pulling actual 30-day or 60-day ROAS or CPA and setting the initial target 10% to 20% looser than that actual number. According to groas, targets should then be tightened in small increments of no more than 10% to 15% per adjustment, with at least two weeks between changes.
Read more: How To Set A Starting Target Based On Historical Performance
According to groas, learning phase resets are triggered by changes to bid strategy type, target values, conversion actions, budget where shifts are significant not minor, and campaign structure. The article states each reset typically lasts one to two weeks and during that period performance is volatile and CPAs tend to spike.
Read more: What Changes Restart The Learning Phase
The article recommends using micro-conversions such as form starts, key page views, or engagement events as observation-only or secondary conversion actions so the algorithm can learn without targeting them directly. According to groas, if a Begin Checkout event is set as a primary conversion alongside Purchase, Smart Bidding will optimize toward the easier, cheaper conversion.
Read more: Micro-Conversions As A Volume Lever: Using Them Without Poisoning The Signal
[1] https://groas.com/post/google-ads-smart-bidding-mistakes-blocking-performance (the article this page answers from)