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Data extraction

What is data extraction?

For scoping reviews, data extraction is referred to as "charting the data". The aim is to create a descriptive summary of the results which addresses the scoping review's objectives, and ideally answers the questions of the review.

A draft charting table/form should have been developed with your protocol, but it is acceptable to refine this at the review stage. 

 

Additionally:

"For ease of reference and tracking, it is suggested that reviewers keep careful records to identify each study. As reviewers chart each study, it may become apparent that additional unforeseen data can be usefully charted. Charting the results can therefore be an iterative process whereby the charting table is continually updated."

- JBI Reviewer's Manual (Methodology for Scoping Reviews, Chapter 11)

  • The information that you extract from the studies included in your scoping review will depend on the purpose of your review and your question.
  • Assessment of eligibility of studies, and extraction of data from study reports, should be done by at least two people, independently.
  • Data collection forms are invaluable. They should be designed carefully to target the objectives of the review, and should ideally be piloted by the review team on two or three articles to ensure that all required data is captured.
  • Tips are available for helping with the design and use of data collection forms.
  • Data may be reported in diverse formats.

What data should be collected for each included study?

According to the JBI Reviewer's Manual (Methodology for Scoping Reviews, chapter 11), key information to chart for each paper includes:

  • Author(s)
  • Year of publication
  • Origin/country of origin (where the study was published or conducted)
  • Aims/purpose
  • Study population and sample size (if applicable)
  • Methodology/methods
  • Intervention type/duration, comparater, outcome measures (if applicable)
  • Key findings that relate to the scoping review question/s

Learn more:

The PRISMA-ScR includes some further guidance:

Data extraction templates/examples

Data extraction using Covidence / EndNote

Covidence

If you are intending to use Covidence to complete your data extraction, the software will take you through two linked processes:

  • Critical appraisal: using an official critical appraisal tool (see video below 0:00 - 3:54)
  • Data extraction/table building (video below, from 3:55)
Note: You do not have to use a critical appraisal tool to assess your references for a scoping review, unless you have stated that you will do so as part of your protocol.

  • If not performing a critical appraisal, skip this step and proceed to data extraction.
  • If you are undertaking a critical appraisal, the PRISMA-ScR offers some guidance.

Video Length: 14:28

Learn more:

Note: after completing your data extraction in Covidence, you must export your data. 
EndNote

Alternatively, you can choose to complete your coding and reporting via EndNote. The following paper explains how:

How to present the results synthesis

Your protocol should include a plan for how you will present your results synthesis.

Your PCC inclusion criteria will assist you in choosing how the data should be mapped most appropriately, but you can refine this toward the end of the review, when you have a better picture of the sort of data available in your included studies.

The results of a scoping review may be presented in your final paper in a variety of ways, including:

  • tables and charts, featuring distribution of studies by year or period of publication, countries of origin, area of intervention (clinical, policy, educational, etc.) and research methods; and/or
  • in a descriptive format that aligns with the review objective/s and scope.
Note: If you present your data in a table/chart, also include a narrative summary to explain how the results relate to your review objectives and questions. 

 

JBI also advise (Reviewers' Manual: 11.3.8.1 Results) the results can also be classified under main conceptual categories, such as:

  • aims
  • duration of intervention
  • intervention type
  • study population (and sample size, if it is the case)
  • methodology adopted
  • key findings (evidence established)
  • gaps in the research

For each category reported, a clear explanation should be provided.

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