Question

In Exercises 29–32, indicate whether the observational study used is cross-sectional, retrospective, or prospective.

Heart Health Study Samples of subjects with and without heart disease were selected, then researchers looked back in time to determine whether they took aspirin on a regular basis.

Short answer

This is a retrospective observational study.

Step-by-step solution

Given information

It is required to look back in time to check for the intake of aspirin for a sample of subjects with and without heart disease.

Types of observational studies

The study is termed across-sectional study when data is recorded at one point in time instead of over a long period.

When data is recorded for a past period to aid the current study, it is called aretrospective study.

When data is recorded for a continuous period, and the relationship between variables is determined using future values, it is called aprospective study.

Identification of the type of study

The study needs the researcher to look back in time to collect data. As the researcher needs past data to determine whether the subject took aspirin, the given study is retrospective.