Ineligible doesn't mean the advert failed

When a recruitment report shows a high ineligible rate, the conclusion usually comes quickly. The ads were wrong. The targeting was off. The quality of the leads was poor.

I think that reading misses something important about who these people are.

Who actually gets ruled out

On one depression study we recruited for, which involved a brain scan, 421 women completed the online screener. 95 were ruled out, each with the reason recorded.

That screener wasn't short. It asked about depression history, substance use and childhood experiences. These are not questions people answer casually.

So every one of those 95 people saw an advert, felt it was speaking to them, and then answered some of the most personal questions a stranger can ask, in the hope there was a place for them in the study.

That isn't a failed lead. That's someone who was interested in the research and wanted to be part of it.

And when you look at why they were ruled out, the advert mostly did its job:

• 34 had a medical reason they couldn't have the scan or take part, such as metal implants, a permanent dental retainer or an IUD.
• 27 lived too far from the research site.
• 20 had a history of substance use the protocol excluded.
• 14 had childhood experiences outside the study's groups.
• 7 were over the age limit.
• 5 hadn't been depressed in the time window the study needed.

Some people had more than one reason. But only five were ruled out because of the condition the study was about. The rest were people the advert reached correctly, who then met a criterion they couldn't have known about.

They deserve a good "no"

If someone has gone that far, the least we owe them is a respectful answer. Tell them plainly that this study isn't the right fit, that it's about the study's rules and not about them, and, where they've agreed to it, that they may hear about other research.

People who feel included even when they don't qualify are people who will look at the next study. They also tell others.

The location question is a balancing act

Distance was the second biggest reason. The obvious fix is to tighten the radius around the site, and sometimes that's right. But it has a cost.

A tight radius can mean a small audience. Show the same advert to the same few thousand people for weeks and you saturate it. Costs go up, and the people you most want start to tune it out.

A slightly wider area lets some people through who live further away. I'd rather have those people come through and be recorded. Some of them would travel. If the study can help with travel, those are participants you'd otherwise never have met. If it can't, you've learned something real about how far your audience actually is from your site.

That's a judgment call for each study. You can only make it if you've captured who came through and where they live.

The "no"s are planning data

This is the part I think gets lost most often.

If you know that, on a protocol like this one, about 23 in every 100 completed screeners won't qualify, and that about 8 of those 23 are lost to a medical list nobody would guess from the advert, you can plan for it. You can budget the next study properly. You can show a sponsor what each criterion really costs in recruitment terms, before the study starts rather than halfway through it.

None of that is possible if the "no"s are thrown away. A percentage on a report tells you nothing. The reasons, counted criterion by criterion, tell you what your recruitment really costs and why.

What I'd ask for

Stop reading the ineligible rate as a grade on the advertising. Ask for the reasons behind it, every month.

Most of them will be people who wanted to take part. Treat them that way, and use what they tell you to plan the next study better.