When you have your final sample of material, you are ready to start extracting data from the material you have selected for your review. The hallmark of a good systematised review is the consistency in which data is extracted from sources
The way you do this will be dependent on the formulation of your question.
Jesson, Matheson and Lacey (2012, 123) give the following example.
a) Bibliographic details
b) Discipline
c) Focus of the paper
d) Method details (sample selection, size, method design, location date etc.)
e) Theory or model used.
The exact nature of this consistent extraction will be specific to the subject matter you are dealing with. The example below provides one way that you could do this.
Taken from: Gough, D. Sandy, O. and Thomas, J. (2017), An introduction to systematic reviews, 2nd edition. London: SAGE
When you are extracting data, you may like to use the PICO framework. Predominantly used in healthcare, PICO stands for:
| P | Population / Patient / Problem | What population or patient group are the investigators working with? It can also refer to the problem being investigated |
|
I
|
Intervention | What intervention is the intervention group receiving? |
|
C |
Comparison / Control | Is there a control group, and if so, what intervention is the control group receiving? |
|
O
|
Outcome |
What outcomes are being measured and how? |
Taken from: How To Use The PICO Framework To Aid Critical Appraisal: https://casp-uk.net/pico-framework/
When you are evaluating your sample, you will need to address any bias that affects the credibility of your study. You may like to use the ROBIS framework to do this. Information about ROBIS can be found here. Although developed with healthcare in mind, you can use the modified documents below to help you.
CASP (2024) How To Use The PICO Framework To Aid Critical Appraisal. Oxford: CASP. Available from https://casp-uk.net/pico-framework/ [accessed 2nd February 2024]
Gough, D. Sandy, O. and Thomas, J. (2017) An introduction to systematic reviews, 2nd edition. London: SAGE
Lacey, F.M., Matheson, L. and Jesson, J. (2012) Doing your literature review: Traditional and systematic techniques. London: SAGE
