Finding the best clinical trial recruitment strategies is critical to attracting patients against the clock.

  • Are you struggling to recruit patients for your clinical trials?
  • Do you find it challenging to reach the right participants for your research?
  • Are you tired of traditional recruitment methods yielding low enrollment rates?

Clinical trial patient recruitment remains a tremendous hurdle that needs to be addressed.

Factors affecting recruitment include overestimating eligible patients, a lack of concern for patients’ needs and preferences, and poorly-targeted outreach. 

Patient recruitment is an expensive and lengthy process – sometimes more than any other clinical trial stage. Thus, effective clinical trial patient recruitment strategies are critical to the time and financial economy of the process.

This article is for:

  • Pharmaceutical companies seeking to optimize patient recruitment.
  • Clinical research organizations aiming to enhance enrollment rates.
  • Researchers and investigators looking for novel approaches to attract diverse participants.
  • Healthcare professionals involved in trial coordination and patient engagement.

We understand the frustrations and complexities of patient recruitment, and through our shared experiences, we aim to empower you with actionable insights and proven strategies to power through this process with confidence.

Patient Recruitment in Clinical Trials

The role of patient recruitment is to effectively reach the required sample size for a clinical trial. Recruitment is the highest cost in a clinical trial and takes more time than any other stage, yet up to 75% of clinical trials fail to meet recruitment targets

There’s a well-documented phenomenon of researchers hugely overestimating the pool of available patients for clinical trials. Lasagna’s Law and Muench’s Third Law both reference this, the latter of which suggests dividing the estimated number of eligible patients by ten to get a more realistic idea. 

For one study, authors looking for 289 IBS patients screened 2149 patients from an estimated pool of 180,000 to reach their target. The process was estimated to take four months and had a budget of $5000. In actuality, it lasted 24 months and cost just over $75,000. 

Sufficient enrollment in clinical trials is necessary to compensate and cover for anticipated patient retention rates, resulting in a large enough pool from which to gather useful clinical data. Therefore, a successful trial depends on a large enough pool of enrolled volunteers, and recruitment strategies need to maximize this pool. 

Why is Patient Recruitment So Important?

Patient recruitment can take longer than any other stage of the study and often the majority of its budget. With low retention rates, recruitment becomes a critical compensatory tactic to ensure the study can run with an effective sample size. 

Clinical trials can improve recruitments using specialized recruitment plans to optimize each stage of the recruitment process for increased attendance. 

Surgical trials are the most unpredictable in terms of recruitment. It’s thought that this is due to the wide range of conditions present for patient populations regarding the complexity of the issues eligible to receive surgical treatment. For example, carpal tunnel is a lot more common and will have a much higher pool of potential patients than something like hip fractures, which occur far more seldom and among a population likely to have a high rate of comorbidities, affecting their eligibility. 

What are Clinical Trial Recruitment Strategies?

clinical trial recruitment strategies

Recruitment strategies in research are the framework, design, and specific approach developed to maximize patient participation for each specific research question. The specific approach will depend on the study population, the budget, and the question being asked. 

Recruitment strategies can take the shape of four main templates

  1. All patients are recruited together, and the trial starts with everyone involved at once;
  2. Recruitment happens in batches as the trial progresses;
  3. Continuous recruitment is employed until the number of desired recruits is reached;
  4. Recruitment is ongoing until a fixed point in time.

Recruitment methods can include referrals, media, text messages, and cold calls, among others. The method of choice will depend on the target population and how expensive it is to conduct and is unlikely to be the only method used. 

Patient Recruitment Plans

A patient recruitment plan aims to maximize enrolment by a series of steps. It typically employs a basic template of:

  • Research – Identify the target audience and any obstacles they may face when joining the trial.
  • Outreach – Establish a budget, and decide on your methods of interacting with your pool of patients.
  • A/B test design – The recruitment process should have different approaches, focusing mainly on recruitment and a backup plan. For example, this A/B method will apply to targeting, media, and messaging. 
  • Advertising – Designing media that will appeal to the target audience while following FDA guidelines.

The key targets are the simplification of the study protocols, knowing the patient population, and achieving the desired sample size. 

Deciding on screening processes, batch, continuous, or time-limited recruitment strategies; as well as sample sizes that are powered to detect the minimum clinically important difference in a comparative study; will all be important steps in the achievement of these targets.

So, it follows that by improving these key stages, patient recruitment can be increased. With this in mind, here are seven popular and effective patient recruitment strategies for clinical trials.

7 Clinical Patient Recruitment Tactics & Strategies

1 – Direct Outreach and Follow-Up 

While researchers are heavily focused on outreach, it can be easily overlooked that the patients themselves have plenty to manage in their own lives. Direct contact and follow-up can mean the difference between a distracted glance and focused attention from potential patients, and this can be as simple as sending text messages to gauge interest and to follow-up. 

With thousands of potential patients in the pool, this personal touch can be achieved with automated services such as Mosio

2 – Referrals

Referrals are by far the cheapest method of recruiting patients. According to the Center for Information and Study on Clinical Research Participation (CISCRP), 64% of the public believes they should learn about clinical research from primary care providers. Yet, only 0.2% of people are recruited this way.

It stands to reason, then, that a strong network of primary physicians would be a low-cost, preferential approach to recruitment and should be prioritized. Effective networking and the regular sharing of eligibility criteria between researchers and healthcare professionals is the key to increasing referrals. 

3 – Social media

While audio-visual and print media have been the traditional approaches to outreach, they’re the most expensive and outdated formats. Digital recruitment campaigns follow patients to wherever they are on social media across any platform. 

This approach is significantly cheaper than most other media approaches in cost-per-recruit. It can involve personal or generalized ads, depending on the necessary precision of the targeting. 

4 – Flexibility

Where possible, it’s important to reduce the impact of the trial on eligible recruits. Removing as many barriers to participation in trials is the most effective way of improving recruitment numbers. One way to do this is to bring the trial to the patient. 

Siteless trials are on the rise, and they work by partnering with local labs to provide a convenient port of entry for the eligibility checks. This cuts down on travel. Decentralized or virtual trial set-ups, where applicable, speed up enrolment times and increase participation. 

5 – Cast a wide net

Patients who have been turned down at the eligibility stage for previous trials are much less likely to apply for a second study. When screening, it can be useful to either screen for multiple studies at once or collect eligibility data compiled for future use. Should patients meet the criteria of future trials, they can be contacted directly to participate. This cuts down on the cost of contacting ineligible patients. 

6 – Factor in patient retention

While retention might be considered a separate challenge, limiting the factors that lead to patients dropping out of trials achieves the same goal. Strategies for this can also be implemented in the selection process. 

Recruitment teams should be employing patient engagement practices and making sure they are available for patients throughout the process. Offering feedback services or educational tools to patients helps them feel engaged and invested in the process. 

 7 – Understand your patients

Little of what has been discussed would be possible without understanding what is important to the patients as stakeholders in the trial process. 

Listening to the Patient’s Voice and incorporating it into the study design at the beginning of the selection process will help tailor the test design, practical applications, and follow-up procedures accordingly. 

Understanding patient preferences will go a long way to increasing recruitment and retention. 


Patients can often feel like guinea pigs in clinical trials, and the process can take too long, or testing can be too invasive. There are many elements to recruitment that need to be considered when looking to improve sample sizes, but the patient’s voice is one of the most often overlooked and can be the most valuable. 

High outreach costs and poor recruitment strategies often lead to failed trials, so identifying and improving weak methods is crucial to improving the function of clinical trials.