Observational study

How it is used

Cohort, case-control, cross-sectional and ecological studies are all observational. They are often the only ethical or practical choice, but they are more open to confounding than trials, so results are described as associations.

Example sentences

1. This is an observational study, so it cannot prove that the diet prevents dementia.

2. Large observational studies first raised concerns about the drug's safety.

Common collocations

• observational data
• observational evidence
• large observational study
• ecological study

Related terms

• cohort studyAn observational study that follows a group of people over time, comparing those with and without an exposure to see who develops a disease or outcome.
• case-control studyAn observational study that starts with people who have a disease (cases) and people who do not (controls), then looks back to compare their past exposures.
• cross-sectional studyA study that collects information from a population at one point in time, like a snapshot, to measure how common a disease, behaviour or exposure is.
• randomized controlled trialA study in which participants are assigned by chance to receive an intervention or a comparison, such as a placebo or usual care, so that the outcomes of the groups can be fairly compared.
• confoundingA distortion that happens when a third factor is linked to both the exposure and the outcome, making their relationship look stronger, weaker or different than it really is.

More terms: Study Design

• systematic review
• meta-analysis