June 17th, 2022

Spanish-speaking patients show strong interest in clinical trial participation in the US.

For a clinical trial to be successful, patients need to be the top priority. However, language barriers faced during the clinical trial process can often result in lower participation rates of non-English speakers, an unsatisfactory patient experience and, ultimately, imprecise data. In the US, the leading country in clinical trial participation each year, language barriers are an inevitable obstacle in research if trials are not prepared to serve various populations.

According to a recent article by CNN, approximately 41 million US residents speak Spanish at home, which equates to roughly 13.5% of the country’s population. Therefore, to better understand how English- and Spanish-speaking populations differ in response to clinical trial participation and how typical barriers affected respondents, SubjectWell fielded a US survey from March to April 2022 of 438 primary English- or Spanish-speaking patients, 224 and 214 people respectively.

Spanish-speaking respondents were more likely to show interest in participation.

Respondents were given a choice between “somewhat likely” and “extremely likely” to show interest in clinical trial participation. Across the board, Spanish speakers responded with a stronger likelihood of participation, compared to English speakers. However, more Spanish speakers reported being “somewhat likely” to consider participation compared to English speakers, meaning interest is more prevalent, but enthusiasm is lower.

Respondents’ likelihood to participate in a clinical trial:

  • English-speaking
  • Spanish-speaking

“Somewhat” or “extremely” likely to participate

66% English-speaking vs 73% Spanish-speaking


“Somewhat” likely to participate


Spanish-speaking respondents were more likely to participate in a trial with bilingual staff.

73% were interested in clinical trial participation

79% were more interested in clinical trial participation if staff was bilingual


Other factors including compensation and medical insurance impact likelihood of clinical trial participation.

Compensation motivated both groups but was stronger for English-speaking respondents. Additionally, respondents without health insurance were more likely to be only somewhat interested (54%) and less likely to be extremely interested (12%) than those with health insurance, suggesting they may need more factors to motivate them to participate.

Respondents’ likelihood of participating in a clinical trial if compensated:

  • English-speaking
  • Spanish-speaking


Overall, the survey provides evidence for stronger interest in participation among Spanish-speaking patients compared to their English-speaking counterparts, along with evidence that Spanish speakers are even more likely to participate if the trial includes bilingual staff. Yet despite Spanish speakers’ interest in participation, Hispanics represent only 11% of trial participants, but make up 18.5% of the general population.

To make up this deficit, this survey found that an inclusive study design for Spanish speakers includes both a bilingual staff and financial compensation. However, the industry is still exploring the best accommodations to provide improvements in patient diversity and remove barriers to patient recruitment. Financial compensation is just one simple but proven way to increase interest in both Spanish- and English-speaking populations and should be considered during study design.

Be sure to check back on our website for more information related to patient recruitment and survey findings.

Have any questions about our marketplace? Reach out by emailing sales@subjectwell.com.