Once you have decided which articles to include in your review, you need to extract relevant data from those studies. This should be done in a structured and systematic way and is usually presented in tables in the final review report.

Tips:

• Extract only the data that is relevant to your research question
• Create a table or data collection form so that you can summarise the data consistently for each study
• Convert all the data to the same units of measurement, where possible
• Make sure your table headings can be easily interpreted by others
• Make sure any abbreviations or acronyms used in the table are explained in footnotes
• Pilot your data extraction method before you start – especially if more than one person is extracting the data.

For more information see our Systematic and systematic-like review guide: Data extraction and synthesis.

Once you have extracted your data, you need to synthesise your data. This involves bringing together your findings from the included studies to describe and explain what your review has found.

If you have found evidence addressing your clinical question, and you are happy that it is of good quality, and have drawn a conclusion, you then need to check its external validity – how well are you able to apply the evidence to your specific clinical scenario?

Are the populations studies similar enough to your patient for the results to apply? (Consider things such as age, co-morbidities or underlying health issues.)

Is the intervention able to be implemented in your particular context (i.e. do you have the same health resource, is the treatment available where your patient is located)?