$5 or $500? 6 factors for clinical study enrollment costs

The cost to enroll a participant in any clinical research study varies depending on many factors. Wayturn helps researchers find participants using digital advertising, and when we estimate costs some factors come up time and time again.

This article goes through 6 factors to help researchers better estimate budget and recruitment timelines for clinical studies.

( Note however that a full cost analysis (which you can get for free from us) will get you a much better understanding of the costs involved for your particular study )

Background – Cost per what?

Digital advertising involves paying to have something shown to an individual. Many of these costs are auction based, so some demographics, geographical areas are more expensive than others depending on how many other advertisers are bidding for the same people. We measure this in terms of cost per 1000 views (CPM – cost per mille).

A common CPM on Facebook in the U.S is $18, so we will use that as basis for this discussion. This means we pay $18 to reach 1000 people, not guaranteeing that they will click or even notice our ad.

But for clinical trials, it doesn’t end with someone seeing the ad as it would in a branding campaign. People also have to take action – click, pass the prescreen questionnaire, and usually also pass a phone screening and clinic screening before enrolling in the study. That’s the cost we are interested in.

However, breaking down the cost for each step can make it easier to compare studies and estimate costs across conditions. So Wayturn estimates costs by starting with the CPM, and adding estimates for prescreen, phone and clinic pass rates if applicable.

So, then it should make sense that the first, and potentially biggest, factor that influences the cost per enrollment is…

1. Your phone screening process

Wayturn’s ads can find eligible participants for you, but their value is heavily influenced by how good your phone screening process is.

Here are some recommendations to reach more leads by phone:

  • Have a dedicated person or team to answer and make phone calls.

    Take note of their capacity, and do not overwhelm them. Wayturn always aims to keep the speed of referrals consistent.

  • Implement a booking system online.

    Let people schedule an available time slot, instead of calling them when it suits you.

    Wayturn can help you handle the calendar system and book phone screening bookings.

  • ONLY allow qualifed people to book phone calls.

    That way they do not waste your time. Wayturn only allows people to book phone screening after they have passed an online prescreening.

  • Call many times.

    If a lead does not answer at their appointed time – do not give up. People miss appointments quite frequently. Wayturn’s best practice recommendation is to call back at least 5 times during different times and weekdays.

2. Benefits for participants

Having clear and strong benefits reduces costs by a lot, by increasing the rate at which people click on your ads. It’s crucial to think about benefits already when getting material approved by your IRB.

Wayturn is used to write promotional materials that get IRB approval fast, all while keeping benefits exciting for participants.

Here are some common benefits that you should make sure to include, if possible:

  • Compensation

    If participants in your research study get paid – try to get language around that approved for advertising. Depending on your IRB, most specific dollar amounts will get declined, but you might be able to mention reimbursement for costs instead.

    Sometimes, Wayturn has success with getting compensation amounts approved for later stages in the advertising process. If you can’t mention $500 on the ad – perhaps it’s OK to mention during the phone screening, or on the website?

  • Health benefits

    Does your study involve any potential improvements in health? Then these need to be highlighted to the highest appropriate degree. If you cannot promise a cure, then call it a ‘potential cure’, for example.

  • Condition-specific improvements

    Similar to the above, but more specific. Is the clinical trial looking to help people with a particular condition? Has the intervention been approved to help people with other conditions?

  • Previous results

    Has the study been conducted for a long time? Results from previous phases? Are there any results we can share with new participants? Even knowing how many people have participated to date is social proof that the study is safe to join.

  • Purpose or aim – who are we helping?

    Finally, many people participate in research for altruistic reasons. Including background details on why the study is being conducted, who it will help, and what importance it has will make enrollments cheaper.

3. Promotional Images

Images and videos are very important. That’s how we catch the attention of people online. Only after they have noticed an ad do they read the words. Here are some things that make good images:

  • Relevant

    Showing a woman smoking in an ad for a research study seeking female smokers is often effective. Because people who smoke realize that it’s about them. However, it might be a problem with your IRB, or company brand, to be associated with images that ostensibly condone controversial behaviors like smoking.

  • Eye catching

    Images and videos with people who look straight at you often work better than those without any people at all. This is true for all advertising, not just clinical trials. But there are many ways to make ads visually appealing.

  • Variation: drawn, scary, hopeful, happy, sad.

    If your clinical study is going to achieve the lowest possible cost per enrollment, it’s important to have many visual angles. Sometimes, the differences between two images is more than a tenfold decrease in cost per lead.

    Showing young women to a study recruiting older women sometimes works extremely well, for example. So images do not always have to be relevant to be attention-grabbing.

    Having variation also gives your study a longer lifetime – ad fatigue kicks in after a while, making people ignore the previous images that have been used. A fresh image can reach new people.

  • Logo

    Showing your logo on ads gives them credibility and makes them stand out from most other ads – that ask people to spend money. Research is after all free to join, often has benefits, and sometimes even monetary compensation. So clearly signaling that it’s a research study is often very beneficial.

4. Testing process

Just launching some digital ads on Facebook is unlikely to give you good results. The true cost is often revealed slowly over time, with expertise and lots of testing.

Two companies – given the same clinical study, promotional material and prescreening process – will perform very differently on a cost per enrollment basis. That’s because digital advertising is complex. Experience can bring costs down tenfold.

Wayturn has advertising experts with hundreds of clinical studies behind their belts. This also means that we have email lists, pixel data, etc to bring you leads very cheaply. Besides, all this data makes estimating costs for new studies much more accurate. Did we mention you can get an estimate for free?

Here are some important factors for testing:

  • Run broad, interest, lookalike and retargeting campaigns. Compare costs.
  • Test all combinations of promotional material, to all viable audiences, to find the lowest cost.
  • Test landing page variations too – headlines, move sections around, images.
  • Test different platforms (Facebook, Instagram, Youtube, Craigslist, Snapchat, Adwords, and so on) to compare cost per prescreen pass, phone pass rates and final enrollment costs.
  • Sufficient time to test all of the above. Short study deadlines increase costs because there is no time to find the best solution.

You want to make sure you pick an advertising partner that is financially motivated and capable of finding qualified leads fast, cheap and in great quantity. That is why Wayturn guarantees a cost per qualified lead up front, following the free cost analysis.

You might also want to test only one partner at a time – because otherwise the CPM costs outlined above increase as multiple advertisers bid for the same views, and you end up with higher costs. One solution is to give advertisers different platforms – one for Facebook, one for Youtube.

5. Study details

People want to know exactly what they are expected to do in the clinical research study after they have signed up. These details need to be written in simple language. Most people do not read everything – so it needs to be concise and important.

Here are some examples of details you want to include:

  • Location. If the location is close to you, the ad gets clicked more often.

    “Join acne study in Manhattan”

  • Hypothetical research questions are very effective at getting people invested in your study, if the topic is relevant to them.

    “Do artificial sweeteners affect glucose?”

  • The name of the research center, university or sponsor should be included in the ads via text, logo, or both. Digital ads are often mistrusted if they do not look trustworthy.

    “The University of Edinburgh is currently enrolling healthy […]”

  • Bckground information. Detailed info and statistics can increase trust and interest.

    “Around 14% of Australian women suffer from endometriosis, but there is currently no known cure. Researchers seek healthy […]”

6. Study Criteria

Your study is likely to have eligibility criteria. These can have more or less impact on final enrollment costs. In general, broader criteria are cheaper because that means there are more potential leads in any given audience.

By the same logic, larger audience sizes means cheaper leads, because the ads can be shown to segments that are more likely to enroll. Segmenting by interests, demographics and other factors is called ‘targeting’ in digital advertising. It’s part of what is tested during campaign optimization.

Here are some specific examples of study eligibility criteria and their impact on enrollment costs:

  • Demographic criteria

    Age, gender and to some degree occupation and income levels is incredibly easy to target using digital advertising. This means that incredibly narrow demographic criteria usually are not a problem. The same goes for specific nationalities and ethnicity. Conditions that are more common in one gender, or an age range, are thus not as hard as you might assume.

    However, children under 13 and elderly above 70 years old are very hard to find with digital advertising. That’s because neither are active online – and often not even targetable. Ads can only be shown to people above 13.

  • Geographical criteria

    Wide geographical areas are cheaper to run ads in because it increases the audience size. Most participants for physical studies come from a 25-mile radius of the research site – broader than that and it takes too long for them to travel, especially if your study has many clinic visits.

    Virtual, online and phone studies have a huge advantage here. It’s easier for participants to join, and easier to find them with advertising because there are more people to target among. This means that our targeting can be more granular, and often much more effective.

  • Health, or condition specific criteria

    Most of your eligibility criteria are likely to fit in here. You might need people with Diabetes, Cancer or Smokers. You might exclude anyone with a BMI over 30, or anyone who isn’t willing to take birth control.


Unfortunately, it’s impossible for us to give you general cost data on all conditions and specific eligibility criteria. We have data from hundreds of studies that we can share with you in a custom analysis for your study though, so you can get a more complete picture.

Finding people who fit all of your criteria, whatever they may be, is Wayturn’s expertise. Digital advertising is perfect for both broad and narrow eligibility criteria. Let us show you what we can do.