Study design

Question 1

What’s a cohort study?

Answer 1

Out of a population of people without the disease, determining who is exposed and who isn’t exposed to the variable in question.

And then over time investigating how many of each cohort develops the disease and how many don’t.

Question 2

What’s a longitudinal study?

Answer 2

A correlational research study that involves repeated observations of the same variables over long periods of time — often many decades

Question 3

What’s a cross-sectional study?

Answer 3

Data collected at a defined time. Used to assess the prevalence of acute or chronic conditions, or to answer questions about the causes of disease or the results of intervention.

Question 4

What’s a case control study?

Answer 4

Identifying cases of the disease and comparing with a control of people without the disease.

Retrospectively comparing the number of people within each category who have been exposed to the variable under investigation.

Question 5

What is a randomised controlled trial?

Answer 5

A study in which participants are assigned to a study group at random.

They are given an intervention and the effects of the intervention are observed

Question 6

What is a prospective study?

Answer 6

Watching for outcomes, such as the development of a disease, during the study period and relates this to other factors such as suspected risk or protection factor(s). The study usually involves taking a cohort of subjects and watching them over a long period.

Question 7

What is an ecological study?

Answer 7

Using routinely collected data - eg a census or death certificates