Responsive Search Ads.

Responsive Search Ads (RSAs) are Google's default search ad format where advertisers provide up to 15 headlines (each up to 30 characters) and up to 4 descriptions (each up to 90 characters). Google's machine learning automatically tests different headline and description combinations to determine which perform best for different users and queries.

RSA vs. Expanded Text Ads

Expanded Text Ads (ETAs) — now deprecated — had a fixed structure: 3 headlines and 2 descriptions always showing in a set order. RSAs allow more asset variety and let Google optimise the combination dynamically. ETAs could no longer be created after June 2022, though existing ones can still run. RSAs give Google more control; ETAs gave advertisers more creative control.

Pinning Headlines

Advertisers can 'pin' specific headlines or descriptions to appear in a fixed position in every ad — for legal disclosures, brand mandatories, or mandatory offer terms. Pinning reduces the permutation testing Google can do and typically lowers the 'Ad strength' metric, but may be necessary for compliance or brand consistency reasons.

Optimising RSA Asset Strength

Google's 'Ad strength' indicator (Poor to Excellent) evaluates RSA quality based on: headline count (more variety = better testing), headline uniqueness (avoid repeating the same theme), inclusion of keywords in at least two headlines, description length (longer descriptions improve score), and variety of ad messages. A 'Good' or 'Excellent' ad strength correlates with better Quality Score and lower CPC.