BioScience Writers LLC
 

Follow us on Facebook Follow us on twitter Follow us on LinkedIn

 
  <     Client Comments    >   
   
  • UCLA
    "I wanted to share with you the good news that the grant you helped me with was turned into two grants (one R01 and one R21) and that they were both recently funded. You can add that to your success stories. Thank you for all the help, it's been invaluable!"
    Patrick A.
    United States

   
  Country   
 
You have our 100% Satisfaction Guarantee!

Writing a Systematic Review Part II:
Identifying literature—Inclusion and Exclusion Criteria

Release Date: August 7, 2017
Category: Scientific Writing
Author: Katherine S., Ph.D., E.L.S.

In our last article, we discussed how to define your aim for the systematic review. Do you remember your aim?

I want to see if treatment P improves disease-free survival and the ability to perform tasks R and S compared with placebo in patients with condition X, and I’ll be using data from randomized controlled trials.

Great. Now it’s time to come up with the inclusion and exclusion criteria for the literature.

My what?

Your inclusion and exclusion criteria are a list of parameters or factors that you use to decide whether you should include a paper in your analysis. It is best to come up with these criteria at the same time as your aim to make sure the results aren’t biased. Sometimes, the criteria need to be changed once you see the number and type of articles that address your aim. However, it is best to define them before you see your search results. You can also build some of the criteria into your search terms, which will reduce the number of articles you get back.

What kind of things do I put in inclusion and exclusion criteria?

There are two types of inclusion criteria: those relating to publication details and those relating to experimental design. Publication criteria can include things like the date of publication, the language in which the article was published, whether the article was peer-reviewed, and whether to include multiple publications on the same study population. Experimental design criteria can include factors such as randomization, level of blinding (e.g., single blind, double blind, blinded assessors), prospective or retrospective studies, enrollment criteria, number of enrolled subjects, follow-up time, and acceptable outcome measures.

All of these parameters can affect your data analysis and the strength of your conclusions. You should also have a solid rationale for selecting these criteria. For example, let’s say you decide to only include papers published after 1980. If the FDA approved a device that had higher diagnostic sensitivity for condition X in 1979, that would be a good inclusion criterion. If you don’t feel like reading a paper published before you were born, that would be a bad inclusion criterion.

Okay. Let’s say that I want articles published after 1990 because data on treatment P was first published in 1990. I want articles published in peer-reviewed journals in English. I only want to include one publication per study population. I want prospective randomized control trials that must have at least 100 patients enrolled because that is minimum number of patients needed to observe a statistical difference with sufficient power. They must also have at least 5 years of follow-up because that is the minimum time to observe disease-free survival.

Those are good inclusion criteria. Now you will need to conduct your search. We’ll get into that in our next article, “Writing a Systematic Review Part III: Identifying literature—Designing a Search .”

Scientific Writing Workshops

Our articles are based on the material from our scientific writing workshops, which cover these and many other topics more thoroughly, with more examples and discussion.

We offer on-site workshops for your event or organization, and also host workshops that individual participants can attend. Our on-site scientific writing workshops can range from 1-2 hours to several days in length. We can tailor the length to suit your needs, and we can deliver a writing workshop as a stand-alone activity or as part of scheduled meetings.

Our scientific writing workshops consistently receive high praise from participants including graduate students, post-docs, and faculty in diverse fields. Please see our scientific writing workshop page for details.

If you found this article helpful or if there is a topic you want us to address in a future article, please use our online comment submission form, or contact us directly. Your comments and suggestions are valuable! Click here to return to our scientific editing article library.