To investigate a 3% decrease in Click-Through Rate, it is essential to analyze several factors. Here are the steps I would follow: Review historical data : It is important to determine whether this drop is part of a trend or a sudden change. I would compare the current CTR with historical data to assess whether it typically fluctuates or remains stable. Examine any recent internal changes : This may include modifications in product design, pricing strategies, or target demographics. Additionally, it would be beneficial to review our advertising content, headlines, and visuals. Look for any Google algorithm updates : Google regularly updates its shopping algorithm, which can influence CTR. Analyze our competitors : It's possible that competitors have recently increased their advertising efforts or enhanced their product attractiveness, resulting in a higher CTR for them and a decline for us. Segment the data : I would categorize the CTR by various segments, such as device type, audience demographics, or geographical areas, to identify any trends related to the decline. Lastly, I would perform an A/B test based on my observations to confirm my hypotheses and collect additional data. This would enable me to propose a strategy to enhance the CTR.