If you’re thinking about participating in a clinical research study, you’re sure to come across inclusion and exclusion criteria. Detailed by the investigators, these characteristics define which people may be included in the study and which may not. They play an important role in clinical research, and they will affect your ability to participate in clinical studies. To better understand the purpose of enrollment criteria, the difference between inclusion and exclusion criteria, and common enrollment characteristics, please scroll down.
Inclusion and Exclusion Criteria in Clinical Research
The Purpose of Enrollment Criteria
Enrollment criteria, which define the patient population to be investigated, play a critical role in research studies. For this reason, researchers are required to specify inclusion and exclusion criteria when designing a new clinical study. These criteria serve several important functions:
- They ensure that the study participants have the characteristics that will make it possible for the researchers to accomplish the study’s purpose.
- They increase the likelihood of the study producing accurate, reliable, and reproducible results.
- They help ensure the safety of participants.
All criteria should have clear scientific or clinical reasoning. For example, a compelling reason to exclude male participants could be that the research is investigating a treatment for breast cancer or menopause. It’s important that the researchers review all enrollment criteria to ensure that no group or individual person is excluded without an acceptable reason.
The Difference Between Inclusion and Exclusion Criteria
The difference between these two types of criteria is quite simple:
- Inclusion criteria are the characteristics that prospective participants must have if they wish to join the study.
- Exclusion criteria are the characteristics that disqualify prospective participants from joining a study.
They are typically written using positive language, avoiding negative clauses:
- If you have an inclusion criterion, you may qualify for the study.
- If you have an exclusion criterion, you are disqualified from the study.
Characteristics Frequently Specified
The characteristics specified in inclusion and exclusion criteria vary from study to study depending on the goals of the research. However, the following factors are commonly identified:
- Age
- Sex
- Race
- Ethnicity
- Weight
- Diet
- Smoker/nonsmoker
- Physical activity
- Medical conditions
- Psychosocial or emotional conditions
- Medications
- Type and stage of disease
- Treatment history
- Practical or logistical issues (participant’s location, language restrictions, barriers to consent)
When selecting these criteria, researchers must balance essential versus trivial details, structure versus flexibility, and scientific ideals versus the real world. If the enrollment criteria are too narrow, the researchers may struggle to recruit a sufficient number of participants. They may also limit how applicable the results of the study are to a larger population of patients. If the enrollment criteria are too broad, the study may fail to reach a meaningful conclusion. This also may lead to increased safety concerns.
Before applying for any clinical study, review the enrollment criteria to ensure that you qualify.
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Have you ever thought about participating in a clinical research study? You could be a part of history! And QPS Missouri is looking for new participants. Since opening its doors in 1994, QPS Missouri has conducted over 2,100 FDA-regulated studies, paying out over $35 million to local participants. Your local participation could have a global impact, as QPS is an international leader in contract research with facilities in North America, Europe, and Asia. Our mission is to accelerate the development of drugs worldwide by enabling breakthroughs in pharmaceutical innovation. If you would like to join us in this mission, consider applying for a clinical research study.
To get started, you simply need to fill out an online application. Within 48 business hours, a recruiting coordinator will contact you for your pre-screening assessment. To learn more, please visit the QPS Missouri website, review the study participation process, or check out our list of FAQ.