Describe a time a campaign did not perform. How did you diagnose and respond?

Work through the funnel in order — the stage where it broke determines the fix.

• Was it seen? Low impressions or reach means a budget, targeting, or bidding problem, not a creative problem.
• Was it clicked? Good reach with poor engagement means the message or creative is not landing, or the audience is wrong.
• Did it convert after the click? Good traffic that does not convert points at the landing page, the offer, or a mismatch between what the ad promised and what the page delivered — which is the most common cause.
• Did the leads become customers? Conversions that never close means you attracted the wrong people, and cost per lead was hiding it.

Then respond proportionately: pause obvious waste immediately, change one significant variable at a time so you can attribute the result, and give the change enough data to be meaningful before judging it.

Note: The most valuable version of this story involves discovering the tracking was wrong, or that the campaign was working and the sales follow-up was the bottleneck. Both are common, both are findings, and both show you look beyond your own function.