Per-asset performance labels (BEST / GOOD / LOW)

Returns Google's per-asset performance labels for responsive search ads — BEST, GOOD, LOW, LEARNING or PENDING — for each headline and description, with the impressions behind them. Use when: the user wants to improve an existing ad and needs to know which parts to replace. Do not use when: the ad is new. Assets stay LEARNING until Google has served them enough, and replacing a LEARNING asset restarts that clock for nothing. The labels are relative to the other assets in the same ad, not absolute quality: in a strong ad, some asset still has to be LOW. Replace LOW assets with genuinely different ideas rather than reworded versions of the BEST one, or the next report says the same thing. If you are unsure which account, campaign or period the user means, ask them — do not guess ids or dates.