Developing your research question is one of the most important steps in the evidence synthesis process. At this stage, you and your team likely have identified a knowledge gap in your field and are aiming to answer a specific question:
If X is done, then will Y occur?
OR assess an intervention:
How does X affect Y?
OR synthesize the existing evidence:
What is the nature of X?
Whatever your aim, formulating a clear, well-defined research question of appropriate scope is key to a successful evidence synthesis. The research question will be the foundation of your synthesis and from it your research team will identify 2-5 possible search concepts. These search concepts will later be used in step 5 to build your search strategy.
Formulating an effective research question takes time and usually requires validation through multiple preliminary test searches. You and your team may go through many different versions before settling on the right research question.
To help formulate your research question, some commonly used frameworks are listed below.
Think of these frameworks as you would regard a framework for a house. A framework is there to provide support and to be a scaffold for the rest of the structure. In the same way, a research question framework can help structure your evidence synthesis question.
Probably the most commonly used framework is PICO:
P Population/problem
I Intervention/exposure
C Comparison
O Outcome
Example: Is gabapentin (intervention), compared to placebo (comparison), effective in decreasing pain symptoms (outcome) in middle-aged male amputees suffering phantom limb pain (population)?
While PICO is a helpful framework for clinical research questions, it may not be the best choice for other types of research questions, especially outside the health sciences. Here are some other options:
P Population/problem
I Phenomenon of Interest
Co Context
Example: What are the experiences (phenomenon of interest) of caregivers providing home-based care to patients with Alzheimer's disease (population) in Mexico (context)?
S Setting
P Perspective (for whom)
I Intervention/exposure
C Comparison
E Evaluation
Example: What are the benefits (evaluation) of using a doula (intervention) for low-income mothers (perspective) in the United States (setting) compared to no support (comparison)?
S Sample
PI Phenomenon of Interest
D Design
E Evaluation
R Study type
Example: What are the experiences (evaluation) of women (sample) undergoing IVF treatment (phenomenon of interest) as assessed?
Design: questionnaire, survey, or interview
Study type: qualitative or mixed method
There are many other research question frameworks. For a variety of examples, see these links:
Seed articles are those articles on your topic that you have already identified as being essential to include in your evidence synthesis, prior to conducting the systematic search. During their preliminary searching or through other means, researchers typically identify at least 2–3 (if not more) articles that they expect will meet their criteria for inclusion. These seed articles are useful for multiple reasons:
Inclusion and exclusion criteria are developed after a research question is finalized but before a search is carried out. They determine the limits for the evidence synthesis and are typically reported in the methods section of the publication. For unfamiliar or unclear concepts, a definition may be necessary to adequately describe the criterion for readers.
Some common inclusion and exclusion criteria include the following: