Question

which two of the following study design are best for assessing temporality, please select two?
a)cohort
b)experimental
C) cross sectional
d) ecological
E) case control

Answer 1

In temporality, cause precedes the effect

(a) Cohort-In this type of study, the sample is selected based on the exposure, and the outcome occurs at a later date, so temporality of the exposure outcome relation is established.

(b) experimental- Experimental studies test the cause effect relationships in a tightly controlled setting by separating the cause from the effect in time. So, temporality is well established.

(c) cross sectional- In this type ofoa study, exposure and outcome are determined at the same time, so no temporality between these two variables can be inferred; therefore no inferences about causality can be made from this type of study design.

(D) ecological- This type of observational study uses aggregate level exposures and outcomes. So, temporality is not well established.

(E) case control- In a case control study design, the ascertainment of exposure is done after the outcome. This means results lack the element of temporality and therefore causality cannot be implied from these studies.

So, correct options are (a) and (b).