Research Study Types There are many different types of research
studies, and each has distinct strengths and weaknesses. In
general, randomized trials and cohort studies provide the best
information when looking at the link between a certain factor
(like diet) and a health outcome (like heart disease). These are
studies done in laboratories on cells, tissue, or animals.
Laboratories provide strictly controlled conditions and are
often the genesis of scientific ideas that go on to have a broad
impact on human health. However, laboratory studies are only a
starting point. Animals or cells are no substitute for humans.
These studies look at the characteristics of one group of people
who already have a certain health outcome (the cases) and
compare them to a similar group of people who do not have the
outcome (the controls). While case-control studies can be done
quickly and relatively cheaply, they aren’t ideal for studying
diet because they gather information from the past. People with
illnesses often recall pa