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Measuring What Matters: KPIs Beyond Clicks and Impressions

This article explores how looking beyond clicks and impressions can help clinical trial teams better measure recruitment performance and focus on the KPIs that ultimately drive qualified referrals and enrollment.

Digital advertising can provide clinical trial teams with more data than ever. Impressions. Clicks. Click-through rates. Cost per click. Video views. Landing page visits. The numbers arrive almost immediately after a patient recruitment campaign launches, which makes them tempting measures of success.

‍But a click isn’t a patient.

‍And an impression certainly isn’t an enrollment. For clinical trial recruitment, the metrics that are easiest to measure are often several steps removed from the outcome that matters: finding eligible participants and moving them successfully through the recruitment process.

That doesn’t make media metrics unimportant. They tell us whether people are seeing a campaign, responding to creative, and reaching the study website. They just don’t tell us the whole story.A campaign generating thousands of inexpensive clicks may produce very few qualified candidates. Another with a higher cost per click may ultimately generate more screenings and enrollments. If we judge those campaigns by media metrics alone, we may optimize in exactly the wrong direction.

Start With the Recruitment Journey

Most digital patient recruitment campaigns follow some version of the same path:

‍Impression → Click → Study Website → Pre-Screener → Potentially Qualified Candidate → Site Referral → Site Screening → Enrollment

‍The exact path varies by study. Rare disease recruitment may require medical-record review or diagnostic confirmation. Some programs use centralized call centers; others route candidates directly to sites. But the principle is the same: a click happens near the beginning. Enrollment happens at the end. What happens between the two is where recruitment performance is won or lost.

Media KPIs Still Matter

There’s no reason to throw away traditional digital metrics. Impressions tell us whether a campaign is delivering reach. CTR helps identify creative that attracts attention. CPC tells us what we’re paying for traffic. Landing-page behavior can indicate whether people engage upon arrival.

Those are useful signals, especially early in a campaign when downstream recruitment data may not yet exist. The mistake is treating them as final outcomes.

A high CTR tells us an ad convinced someone to click. It doesn’t tell us whether that person has the condition being studied, lives within a reasonable distance of a site, meets the major eligibility requirements, or has a realistic chance of enrolling.

Qualification Changes the Picture

Pre-screener completion is one of the first metrics that begins to tell us something about recruitment intent rather than advertising response alone.

If people start a pre-screener but don’t finish it, something is happening. The questionnaire may be too long. A question may be confusing. The mobile experience may be frustrating. Or the advertising may have created an expectation that doesn’t match the study.

Then comes qualification rate: the percentage of respondents who appear to meet the study’s initial eligibility requirements. This is where top-of-funnel performance can start to look very different.

As an example, in Stark Raving Health’s obesity clinical trial campaign, the objective wasn’t simply to drive a large response. The study needed people with a high BMI who were otherwise in good health — a much more specific audience than “people interested in weight loss.” Precision targeting and continuous optimization produced 1,000s of qualified referrals in just days. The campaign also generated double-digit click-through rates across platforms and ultimately completed enrollment two months ahead of schedule. The CTR was impressive. Qualified referrals and accelerated enrollment were the real results.

That distinction matters. The ad that generates the most responses isn’t always the one that generates the best candidates. Once qualification data begins coming in, the apparent winner can change.

Cost Per Qualified Candidate Tells Us More

Cost per click tells us what we paid for traffic. Cost per qualified candidate tells us what we paid for someone who might actually be useful to the study.

‍Campaign Spend ÷ Potentially Qualified Candidates = Cost Per Qualified Candidate

‍Once campaigns are viewed this way, channel performance can shift dramatically. Search may cost more per click but produce stronger intent. A patient-community placement may generate less traffic but a higher proportion of relevant respondents. Broad social may produce inexpensive clicks that require much more filtering.

The point isn’t that one channel is universally better. It’s that the value of the channel becomes clearer when the KPI moves closer to recruitment.

Rare Disease Recruitment Makes the Point Even More Clearly

Our recent hereditary angioedema (HAE) campaign is a useful example.

HAE affects roughly one in 50,000 Americans, and the Phase III study needed 80 patients with documented attacks in the previous six months across 25 U.S. research sites. A huge response volume would have meant very little if those responses hadn’t been from the right people.

The campaign generated more than 250 qualified, pre-screened referrals and randomized 85 patients, exceeding the study target. 27% of qualified referrals progressed to randomization, and the cost per randomized patient was 30% below industry benchmarks. Enrollment finished one month ahead of schedule. Those numbers explain whether the campaign worked.

Qualified referrals. Qualification-to-randomization rate. Cost per randomized patient. Time to full enrollment. CPC can help manage the media buy. It can’t tell that story.

The Handoff Matters

A potentially qualified candidate still has to reach the site.

That makes referral-to-site rate, contact rate, and speed-to-lead important parts of campaign measurement. How quickly does a site attempt contact? What percentage of referrals are reached? How many schedule a screening visit? How much time passes between referral and screening? These aren’t traditional advertising metrics, but advertising performance can’t really be understood without them.

If a campaign is delivering qualified candidates and those candidates wait days for follow-up, changing the creative won’t solve the problem. Sending more leads probably won’t either. Sometimes the best recruitment optimization has nothing to do with the media plan.

Screen Failures Are Data, Too

A digital pre-screener generally can’t replicate site-level screening. Medical records, laboratory values, medication history, diagnostic confirmation, and other protocol criteria may not be available at the time of initial qualification. Some screen failures are inevitable. Patterns are what matter.

If candidates repeatedly fail for the same reason, can that criterion be addressed earlier? Can the advertising be more specific? Is the targeting reaching an audience that looks right demographically but isn’t right clinically? The goal isn’t zero screen failures. It’s to learn from the ones we’re seeing.

Different Channels Have Different Jobs

One of the easiest ways to misread campaign data is to expect every channel to perform the same way. Search captures existing intent. Social can introduce research participation to people who weren’t actively looking. Programmatic expands reach. Digital Out-of-Home can build recognition in health-relevant environments. Advocacy organizations and physicians can add trust and access that media alone cannot.

The HAE campaign illustrates the point. Social media accounted for 45% of enrolled patients, advocacy partnerships for 35%, and physician referrals for 20%.

Those channels didn’t do the same job. Digital targeting helped identify a very small patient population. Advocacy relationships provided credibility and access within a tight-knit rare disease community. Physician referrals created another trusted route to potential participants.

Looking only for the cheapest click would miss the point entirely. The better question is: What did we expect this channel to accomplish, and which KPI tells us whether it did?

More Leads Aren’t Always Better

The contrast between the obesity and HAE campaigns makes this especially clear.

For the obesity study, scale and precision could work together: 1,000s of qualified referrals were generated, whereas HAE required a completely different approach. With an ultra-rare population, the objective was never enormous lead volume; it was finding enough of the right people to reach a demanding enrollment goal.

Both campaigns succeeded. Success simply looked different.

This is particularly important for studies with restrictive eligibility criteria. Tightening an audience or making the recruitment message more specific may reduce total response. On a conventional media dashboard, that can look like a step backward.

It may actually be an improvement if a larger proportion of those respondents have a realistic chance of qualifying — and if sites spend less time processing people who were never likely to enroll. Sometimes optimization means deliberately generating fewer leads.

Look at the Sites, Not Just the Campaign

National averages can hide a lot.

One site may receive a steady flow of qualified candidates and convert them efficiently. Another may receive similar traffic but very few viable referrals. A third may receive strong referrals and struggle to contact them.

Site-level reporting helps answer better questions: Where are qualified candidates coming from? Which sites convert referrals into screenings? Where would more media actually help? And where would more media simply create more unconverted leads? Clinical trial recruitment is local. The reporting should reflect that.

Cost Per Enrollment — and Enrollment Velocity

Eventually, the funnel reaches the metric sponsors care about most: the cost to produce an enrolled or randomized participant.

Cost per enrollment brings media efficiency, audience quality, screening performance, site execution, and protocol realities into the same equation. But cost isn’t the only downstream measure that matters. Speed matters, too.

Useful measures can include qualified candidates per week, screenings per site per month, enrollments per site per month, time from referral to first contact, and time from campaign launch to full enrollment.

A study can eventually hit its enrollment target and still miss its timeline. The HAE and obesity campaigns are good reminders that finishing one month or two months early is itself a meaningful recruitment outcome.

Attribution Is Messy

Patients don’t behave like attribution models.

Someone may see a social ad, hear about the study from a family member, encounter an advocacy resource, search for the condition later, and finally return directly to the study website.

Which channel gets credit? There isn’t always a clean answer. Last-click attribution overvalues the final interaction. First-click can overvalue initial awareness. Multi-touch models add context but still depend on what can actually be measured.

UTM tracking, referral-source questions, call tracking, site-level data, search behavior, geography, and conversion paths can all help. The goal isn’t perfect attribution. It’s enough information to make better decisions.

A Dashboard Should Tell You What to Do Next

Recruitment dashboards can become impressive collections of numbers. That doesn’t necessarily make them useful.

A good dashboard should help answer practical questions:

Should we increase spend around a particular site?
Is a creative concept driving traffic but poor-quality candidates?
Are people abandoning the pre-screener?
Are qualified referrals waiting too long for follow-up?
Is one channel expensive at the top of the funnel but efficient at enrollment?

If the dashboard can’t help to answer those questions, adding another chart probably won’t help.

The KPI Should Move Down the Funnel

At launch, downstream data may not exist. So we work with what we have: impressions, clicks, landing-pa

ge activity and pre-screener starts. Then better data arrives: completions, potentially qualified candidates, site referrals, screenings and enrollments.

As that happens, optimization should move downstream, too. A campaign shouldn’t still be congratulating itself for a strong CTR three months later if the traffic isn’t producing patients.

The KPI should mature with the campaign.
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Final Thoughts

Clicks and impressions aren’t bad metrics. They’re just early ones. They tell us whether people are seeing and responding to recruitment advertising. But clinical trial recruitment doesn’t end when someone clicks.

We’ve seen that distinction play out across very different recruitment challenges. For an obesity study, 1,000 qualified referrals in 10 days helped drive enrollment two months ahead of schedule. For an ultra-rare HAE study, success meant finding 250+ qualified referrals, randomizing 85 patients, converting 27% of qualified referrals to randomization, completing enrollment a month early, and reducing cost per randomized patient by 30%.

Different populations. Different recruitment challenges. Different strategies. And different numbers that mattered. A recruitment dashboard should tell us more than whether advertising is generating attention. It should tell us whether the right people are moving through the recruitment process — and where they’re getting stuck when they aren’t.

Because ultimately, we’re not trying to generate the most traffic. We’re trying to help the right patients find the right studies and successfully move from awareness to participation. That’s what matters. And that’s what we should measure.

Stark Raving Health develops and manages clinical trial patient recruitment campaigns with measurement built around the complete recruitment journey — not simply the top of the media funnel. From audience strategy and media optimization to pre-screening, site referral, and recruitment analytics, we help sponsors and CROs understand what’s working, where candidates are being lost, and where recruitment investment can be more effective.