Canadian Health Information Management Association Practice Exam

Which of the following characteristics is NOT associated with a retrospective study?

1. It is relatively inexpensive.

2. Relative risk may be estimated from the results.

3. Incidence rates may be computed.

4. Assessment of past exposure may be biased.

The correct answer is: Incidence rates may be computed.

In the context of retrospective studies, the characteristic that stands out is that incidence rates may not be computed. Retrospective studies typically analyze existing data from the past to identify correlations between exposures and outcomes. Since these studies look back into already collected data, they generally focus on existing cases of a condition rather than tracking new cases over time. Incidence, which refers to the number of new cases of a condition within a specific time period, is usually a favorable measure in prospective studies where participants are followed over time. In a retrospective study, researchers are limited by what data exists and often can only measure prevalence— the total number of existing cases— at a given moment rather than how many new cases occurred during the study period. This understanding underscores the importance of recognizing the limitations of study designs. In a retrospective study, the characteristics of cost-effectiveness, the ability to estimate relative risk, and the potential for bias in assessing past exposures remain valid, but the computation of incidence rates does not align with the typical methodology utilized in such studies.