Cohort studies are prospective in nature.
You suspect that, for example:
- Exposure to a particular chemical, water from a particular source, etc. seems to lead to a particular disease state, or;
- Treatment with a particular procedure or medication seems to lead to a resolution of particular symptoms.
So you set out to examine some representative cases very closely to see if you are correct. As always, it can be exciting to think that you may have noticed something that no one else has noticed, and you want to proceed according to certain rules to insure that you remain honest and prudent.
Here is a simple schematic of the Cohort study:
It is important to note that what makes the Cohort design "prospective" in nature is that you are working from suspected cause to effect (or outcome). It can be a concurrent study, meaning that you start collecting data now; non-current, typical of a chart review or review of other records, or; a combination of the two.
Remember that:
- You can substitute any outcome of interest for Diseased versus No disease (e.g., chronic high blood sugar versus not chronic high blood sugar), and;
- You can substitute Treated versus Not treated for Exposed versus Not exposed.
As in any good study, you need to give serious attention to:
- Stating a hypothesis (or hypotheses), or at least some well-focused research questions
- Carefully defining the population to which your study should generalize
- Selecting an appropriate research design (BEFORE you start collecting data - PLEASE get help if you are unsure)
- Ensuring the objectivity, precision, and reliability of your measures
- How you will draw justifiable and defensible conclusions (i.e., what will you need to be able to do this)
Return to analytical designs.