Here are the most common causes:
1. Increased Auction Competition
Even on branded terms, competitors may start bidding aggressively using your brand name as a broad or exact match keyword. This shifts the auction dynamics and can lower your expected CTR relative to others.
2. Decline in Click-Through Rate (CTR)
If your CTR has dropped—possibly due to ad fatigue, new competitor ads, or changes in how Google displays SERPs—your expected CTR (a key Quality Score component) takes a hit. Google recalculates this frequently.
3. Account or Campaign Restructure
If you recently:
Moved keywords to a new campaign or ad group,
Changed match types,
Altered device or geo targeting,
Google may re-evaluate historical performance, which resets Quality Score temporarily.
4. Hidden Landing Page Issues
Even without visible changes, the landing page may:
Load slower than before,
Have mobile rendering problems,
Trigger redirects or tracking errors.
Use Google’s PageSpeed Insights and Mobile-Friendly Test to rule these out.
5. Ad Copy Misalignment
If your ad copy has diverged even slightly from the branded term (e.g., using a slogan instead of the brand name), Google may score it as less relevant—especially if competitors are now more direct.
Next Steps:
Check historical CTR trends
Review auction insights for new competitors
Test a fresh branded campaign with tighter ad-copy-to-keyword alignment
Monitor landing page load times and mobile UX
Even subtle shifts can dramatically affect Quality Score in a competitive environment.