top of page

Clinical trials probably don’t include people like you, here’s why that matters

Hello, I’m Heidi, and I do research to make clinical trials more inclusive. In this article, I’m going to share some of my knowledge, explain why improving trials is so important in our mission to improve health, and hopefully encourage you to share some of my passion and excitement for the subject too.

First things first, what is a clinical trial?

Clinical trials offer a way to rigorously test health interventions to ensure that they are safe and effective. Health interventions include medications, types of surgery, medical devices, talking therapies, lifestyle behaviours, and more.

In trials, participants are usually split into two groups: those that will receive the intervention and those that will receive the control. A control group may make you think about placebos or sugar pills, but that isn’t always the case. In phase three trials, if there is already a way to manage or treat a condition, we commonly use "usual care" or "treatment as usual" as our control group as our aim is to find a new intervention that improves on the current standard of care.

The feature that makes trials unique is the way that participants are split into those groups; typically, we use a technique called randomisation. Participants do not choose which group they would like to be in, instead, they are randomly allocated, which prevents selection bias from creeping in. If there are specific characteristics of people that might impact the outcome of the intervention, then these characteristics are distributed across the groups and controlled for, meaning that any difference that we see in the outcome of the research can be explained only by the intervention.

My experience is in phase three trials, where the safety of the intervention for people has already been tested over a period of weeks or months. Phase three trials aim to evaluate an intervention’s effectiveness in a bigger group of participants and to gather safety data over a longer timescale.

What about the research to improve clinical trials?

Just as interventions can be improved, the way we evaluate them can be improved too. I do research that explores how to design trials to ensure that their results apply to more people.

Methodological changes might require more time or money, but in the long term, I believe it will save money and improve health. If individual trials provide results that apply to more people, specifically people that are currently under-served by health research, we can avoid the need to do more trials in the future.

Mental ill health is experienced by people with various characteristics. A trial that is testing an intervention that could alleviate the symptoms of mental ill health should therefore include a diverse range of people with those characteristics. For example, if a trial only includes white women under the age of 35, we will struggle to apply the trial’s results to anyone that is not a white woman under the age of 35.

We cannot confidently apply the trial’s results to groups of people that have not been represented in the trial population.

If you are not represented, you are under-served.

Being underserved by health research can be the result of a few different things:

  1. Lower inclusion in research than would be expected from population estimates.

  2. High healthcare burden that is not matched by the volume of research designed for the group.

  3. Significant differences in how a group responds to or engages with healthcare interventions compared with other groups, with research neglecting to address these factors.

It is important to note here that most differences between people are not biological. The characteristics that influence how people approach a trial are largely due to cultural or social differences. Understanding why people do or do not engage with trials means that they can be designed to reduce barriers and increase facilitating factors. Participant populations of most trials are not as diverse as the wider population, leaving much of our society under-served by the research that we do.

Who is under-served by health research?

According to the UK’s National Institute for Health and Care Research INCLUDE project, if you identify with any of the following factors, you are currently under-served by health research:

  1. Demographic factors: Age extremes, women of childbearing age, minoritised ethnicity, LGBTQIA+, and educational disadvantage.

  2. Disease-specific factors: Rare disease, genetic disease sub-types, and brain cancer metastases.

  3. Health status: Mental ill health, people without the capacity to consent for themselves (e.g., psychosis), pregnancy, learning or physical disabilities, smoking, multiple health conditions, and addiction.

  4. Social and economic factors: Full-time employment or unemployment, military veterans, living in remote areas, carers, language barriers, digital exclusion, socioeconomic disadvantage, and alternative residential circumstances (e.g., migrants, asylum seekers, care homes, prison populations, traveller communities, and homeless people).


The fact that clinical trials probably do not include people that look like you is part of the reason for the avoidable health inequalities based on ethnicity, gender, and socioeconomic status that we see in society today. That is why it matters that clinical trials probably do not include people like you.


bottom of page