Iterative Systematic Reviewing: From a Targeted Search to Labelling and Minimalistic Data Extraction

5 min readMar 8
Systematic Review versus Iterative Systematic Review

It is always recommended to start a systematic review by writing a protocol for a research question. If you are dealing with a broad topic with many research questions and gaps, we recommend scoping reviews, which are again based on preset protocols.

Sometimes, a scoping review also works as a sample size calculation method for future systematic reviews informing the number of included studies for the systematic reviews resulting from the scoping review.

What if writing a protocol for the systematic review is not feasible, or if we have to keep the protocol very flexible?

Tailoring the Systematic Reviewing for Your Needs

It is not always straightforward to choose the type of your literature review from the list of over 50 review types. You may need to tailor the systematic reviewing process to your needs.

We had faced a couple of reviews in the past four years when we dealt with broad systematic reviews without a complete protocol. We had to make pragmatic decisions based on limited available time (3–6 months), a high number of search results (between 100,000–200,000), a limited budget, and a limited number of reviewers.

Example: A cheap intervention that makes the world better, with few manageable side effects. Yeah, do that systematic review, mate!

The Concept: Iterative Systematic Review (ISR)

When dealing with systematic reviews with one or two main concepts in broad topics when it is not possible to have a preset protocol because of a lack of knowledge on the topic or limited resources, the review team writes parts of the protocol as they proceed with tasks. Some broad “What Works” and “Gap Analysis” reviews could be among the reviews that setting a pre-specified protocol may not be possible. Such reviews can follow an Iterative Systematic Reviewing process where they run a more targeted search to get fewer results (less than 20,000). Then, two review team members use…


An Evidence Scientist with a Pinch of Career and Life Lessons