Phone Screening: The Do’s and Don’ts

Phone screenings are often the first real human contact that patients have with researchers and study sites during the recruitment process. Before this stage, if a clinical study is being advertised online, recruitment may consist of clicking buttons and typing answers on a computer screen. For many patients, the process of being enrolled in a clinical study often doesn’t feel “real” until this first stage of human contact.

This means the phone screening process is an extremely important step in terms of successful enrolment. In fact, it is the “make or break” point in clinical trial recruitment. And believe it or not, the most difficult part of this crucial stage is simply getting the patient on the phone!

By failing to adhere to best practices for phone screenings, clinical study sites could inadvertently cause the whole recruitment process to come crashing down. Here’s what you need to know to make sure your phone screenings are a success, including our top 5 tips; do’s and don’ts; and how to prepare for setbacks.

Top 5 Tips for Success

5. Use a local number, not a private number.

When possible, use a local number when calling patients, not a blocked or private number. Studies show that telephone call recipients are much more likely to answer when the call is coming from an area code they recognise. For example, Australia-based researchers should use a mobile number (beginning with 04). For researchers in the United States, this number should have a local city, state, or regional area code.

4. Keep in mind patients’ “best time to call” preferences.

While there is a true “golden hour” for calling patients (more on this later), it’s also important to pay attention to each patient’s preferred contact times. If they’ve indicated a best time to call, it’s probably for a good reason.

Many patients with 9 to 5 jobs may not be able to receive non-work calls during the day, making evenings and weekends a popular “best time to call.” Research sites may have trouble accommodating this, but try to make it a priority. If you don’t, you could potentially lose viable patients.

3. Always leave a voice message.

It’s crucial that researchers leave a voice message at every single point of contact. Even if it’s your third time calling that day or if you’ve called every day of the week, we’ve found that your rate of enrolment success significantly increases if you leave a message with a return phone number each and every time you call.

2. Be pleasantly persistent.

In our experience, we’ve found that the average number of attempts it takes for research sites to get in touch with potential patients is between 3 and 5. This means that phone screeners must be persistent and not give up when they don’t get in touch with patients on the first (or even a second, third, or fourth) try.

Many researchers call or email their patients once and expect the patient to get back to them. However, this method almost always results in extreme under-enrolment. Don’t worry about whether or not you’re “bothering” the patient by calling more than once. They expressed interest in your study for a reason and it’s up to you to get in contact with them. Don’t be discouraged or lose momentum if patients don’t answer the phone 2 or 3 days after your first try. It may be tempting to believe they were never truly interested, were unlikely to enrol into the study, wouldn’t have been a good participant, would have dropped out, or other false thoughts. None of this is likely true, as patients have little information to go on when they sign up.

Remember how little patients have committed when they first expressed interest in your clinical trial. It’s not uncommon for their interest to wane rather quickly, but once they learn more about the study and commit more – go through phone screening, ask questions about the study, come in for an initial visit, speak to the researchers, and actually decide to participate – they are much more committed

A good rule of thumb is to call every day for at least a week. Our experience shows that the odds of successful enrolment decreases to 25% after 3 days have passed; and decrease another 5% each day after that. It may be useful to expand the mediums you use to reach patients as you’ll have a better chance of getting a hold of them. For example, it’s appropriate to send a text after 5 days and an email after 7 days, but never at the expense of a phone call.

It can also be beneficial to scatter the timing of your calls. If your first attempt at contact was in the morning, try again in the afternoon, evening, and on different days of the week. It also increases your success if you leave a message to let them know exactly when you’ll be calling again so they know to expect your call at that time.

1. Call patients immediately.

The most important thing you can do to ensure the success of your phone screenings is to call referrals immediately after they sign up. Specifically, return calls to possible participants within one hour of receiving their indication of interest. This is known as the “golden hour.” Not surprisingly, there is a significantly higher chance of making contact with a patient minutes after learning of their interest than making contact even a full hour later.

Statistically, calling patients within one hour yields significantly higher success rates in terms of both reaching the patient on the first try and successfully recruiting them. At this time, patients are likely to feel excited about their possible participation in the trial and are not likely to have changed their minds.

Enrolment potential declines rapidly after this first crucial hour. Why? Because everyone has very busy lives and so much competing for their attention. While this may be impossible for some applications, it’s important to make a significant effort to reach participants within this critical window. Consider making a goal to reach every participant within an hour after they express interest and strive to hold everyone accountable.

Phone Screening Do’s and Don’ts


  • Be professional and discreet.
  • Display empathy towards the people you’re speaking to.
  • Expect patients to answer “yes or no” questions in more complicated terms. Many patients may not have full knowledge or understanding of how some types of questions relate to them, so be prepared for them to expand upon their answers.
  • Build a rapport with patients by being friendly, welcoming, and helping put them at ease.
  • Use clinical language only when appropriate. Understand research terminology enough to clarify in plain language for the patient.
  • Give them something to be excited about toward the end of the call. Help the patient to feel enthusiastic about being involved in the the study. This will solidify their participation and will help them feel that they are making a positive impact.


  • Speak in cold and overly-clinical terms.
  • Say you’re going to call back and then don’t call.
  • Call on public or national holidays
  • Downplay the patient’s condition. Even if you feel their condition is minor in comparison to other patients, don’t say so to them. You never know how it could affect them.

Preparing for Setbacks

While clinical study sites may do their best to follow these tips for success, there are still some factors that can sneak up and hinder results. So, it’s important to look ahead and prepare for these possible setbacks. For instance:

  • Does your study site truly have sufficient staff to complete phone screenings with the required level of care and consideration? If staff are still actively seeing patients on-site, they can’t rush off during the middle of patient meetings to return calls at specific times.
  • Can your site staff accommodate phone screenings outside of working hours, when the site is typically closed and no one is usually on-duty?
  • Are your staff properly trained and prepared for completing phone-screenings? Do they feel comfortable and confident in the process?

Oftentimes, study sponsors can help sites overcome these obstacles by providing them with necessary resources, such as additional staff who can work outside of regular business hours. In some cases, it may actually be best to find a third party agency separate from the study site who can completely manage phone screenings.

Be honest about how prepared your study site truly is for phone screenings and don’t hold back on making adjustments that ensure the success of the trial.

There’s a lot that can go wrong in the phone screening process and you can throw away a lot of energy and advertising money by doing the process sub-optimally. With limited patient populations, you may be inadvertently turning away patients who would have enrolled that can not be replaced. But by following these best practices, you’ll ensure that your phone screenings go as smoothly as possible. It won’t always be an easy process – in fact, you’ll rarely enrol anyone after just one call. But if you remain optimistic, flexible, and persistent, you’re sure to meet your recruitment goals and guarantee the success of your clinical study.

Interested in learning more about clinical trial phone screenings? Need help preparing your site for clinical research? Contact us today to find out how Trialfacts can help!

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