When you extract data about the design of each study, you’re looking for key information about how the authors conducted their research.

Here are some common pieces of data to collect:

What type of study design was used (remember RCTs and Cohort Studies?)

Where was the research conducted?

When was the research conducted?

If the research was randomized, how was the randomization accomplished?

If the research was conducted at multiple centers, how many?

How long were participants followed?

Who funded the research?

How did researchers handle missing data?

You’ll also want to extract data about whether patients, clinicians and outcome assessors knew if participants were receiving the intervention or the comparator. In other words, were these studies blinded? Was it even possible to blind these studies?