Your question is Diagnose a Conversion Drop. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You are a senior product analyst on a consumer lending flow. Over the last 14 days, application completion rate fell from 18.4% to 15.9%, while total application starts stayed flat at about 240,000 per week. The drop began right after a new prequalification step launched for 40% of traffic, and the team also shifted more paid search spend toward mobile web. Leadership wants to know whether the decline is real, tied to the product change, or explained by traffic mix.
How would you investigate whether a drop in conversion is caused by a product issue, a traffic mix shift, or an experiment artifact?