Why does it look like an ad with a high Quality Index doesn have a high click-through rate?
This might occur due to one of several reasons: • Because quality index is indicative of an ad’s performance relative to competing ads, even an ad with a high click-through rate might have a low quality index if competing ads have higher click-through rates. • Click-through rate can fluctuate on a daily basis. Because the displayed click-through rate is dependent on the chosen date range, any short date range might show a click-through rate that seems out of synch with the quality index. Quality index, which cannot be modified by data range, is a historical indicator that will smooth out daily click-through rate fluctuations. Quality index is updated daily based on the previous day’s clicks and impressions. • Quality index is composed of both expected performance and historical performance factors. As an ad receives more impressions and clicks, the historical performance has a greater influence on the quality index.
