What does randomization mean for research
volunteers? [Intro]
Hello! The Federal Office for Human Research Protections,
or OHRP, created these videos to help you learn more about participating in research. Deciding if you want to volunteer for a research
study can be difficult, and this decision can have important consequences. Research that compares interventions or treatments
commonly uses “randomization” as part of the study design, which means that volunteers
are assigned randomly to particular study “arms,” or groups. Which intervention or treatment the volunteers
receive depends on the study arm they are assigned to. This video provides some basic information
about why researchers use randomization in studies and what randomization means to you
as a potential research volunteer. [What does “random assignment” mean?] When something happens “randomly,” that
means it happens completely by chance, and that no one can predict or control the result. Drawing numbers out of a hat to separate people
into two teams is a random procedure. So is flipping a coin to decide who goes first
in a game. Randomization is a commonly used procedure
in clinical research. Research volunteers may be randomized to different
arms in a study. This means that a volunteer’s assignment
to a particular study arm is by chance, and that it is not planned or controlled by the
researcher, the volunteer’s doctor, or anyone else. Which study arm a volunteer ends up in is
random, like whether a coin flip comes up heads or tails, without any input from the
study team. [Why is randomized assignment used in research?] Researchers use randomized assignment to help
get reliable answers to research questions. Suppose researchers want to know if a new
drug can help people fight an infection better than one already being used. They enroll volunteers who have the type of
infection the drugs are supposed to treat. Then they randomly assign volunteers to one
of two study arms. In one study arm, volunteers receive a drug
that is currently prescribed by doctors. Volunteers in the other study arm receive
the new, experimental drug. Then researchers collect information about
how the volunteers in each group respond to the different drugs. If the researchers get to decide who gets
which drug and don’t use randomization, they might unintentionally give people who
seem sicker the new drug—perhaps because they think the new drug might work better,
or maybe they would give sicker volunteers the commonly-used medicine, because they have
more experience with it. But if either of those things happened, the
results of the study wouldn’t tell researchers whether one drug really works better than
the other because the volunteers in each arm are too different from each other. A difference in results between the two study
arms might occur just because one arm includes sicker volunteers. To make sure that any differences in results
between the study arms are caused only by the different drugs, the volunteer groups
need to be similar in health and other characteristics. Like the saying goes, it’s important to
compare apples with apples. Randomization is supposed to help make the
groups more similar. When volunteers are assigned randomly to the
study arms, no one controls which group a volunteer will be in. Therefore, as long as there are enough volunteers,
the study arms should be similar. In our example, each study arm would have
roughly the same number of volunteers with mild and serious infections, and be generally
similar in other characteristics. This way, the only thing that is different
between the two groups is the drug they take. The researchers can be more certain that any
differences in the results are caused by the drugs being studied and not the characteristics
of the volunteers in the groups. This is why randomized studies can produce
more reliable results. Sometimes researchers take additional steps
to avoid unintentionally influencing the results. For example, they may design the study so
that volunteers won’t know, or are “blinded” to, which group they are in. Other times, both the researchers and the
volunteers don’t know which group the volunteers are in. This is called a “double-blind” study. It ensures that no one can intentionally or
unintentionally influence the results. Double-blind randomized studies are one of
the best research designs and generally produce the most reliable results. [So what does it mean for research volunteers
to be “randomized”?] If you are asked to participate in a research
study with a randomized design, here’s what you need to know:
• Your assignment to a particular study arm or group is done randomly, like a coin
flip. The research team cannot choose which group
you end up in. • Similarly, your doctor cannot choose which
study arm you end up in, even if she or he thinks that one group might be better for
you than the other. Your assignment to a study arm is entirely
by chance. • You also cannot choose which group you
are in, and you may not get the one that you want. • It is possible that the researcher, your
doctor, and you will not know which study arm you are in, and won’t be allowed to
find out as long as the study is still going on. • It is important to remember that, unlike
medical treatment, research is not designed to specifically address your needs and interests
as an individual patient. The care that you receive in a research study
does not necessarily put your individual interests first, will not necessarily benefit you, and
could even be harmful, even though there are protections in place. Research volunteers can help science answer
specific medical or behavioral questions. Researchers hope that these answers will contribute
to a better understanding of human biology and behavior, and lead to more effective medical
treatments in the future. [Closing] This video was designed to answer some basic
questions about randomization in research and give you some things to think about. Deciding whether to participate in research
can be hard. Don’t be afraid to ask the research team
for more information and talk with them about your concerns. It’s their job to give you the information
you need so you can make the most informed decision about whether to participate. OHRP has created a variety of resources to
help you think about research participation. For more information, check out our website
at www dot hhs dot gov forward slash about dash research dash participation.