You may already know what topic you want to do your systematic literature review on, however, before starting your review, you must write a focused research question that your review will answer.
For example, you might be interested in delayed prescriptions of antibiotics for patients with respiratory infections. On its own this topic is too broad for a systematic review, therefore you must determine what aspect of the topic you would like to research, and write a focused research question based on this.
Preliminary searches will help you:
Identify and narrow down your question
Ensure that a review of the same topic has not been done recently
Identify key studies
You should do your preliminary searches on whichever searching platform you are most comfortable or familiar with. For many of you this will be PubMed. The example below shows a very basic preliminary search I might use to help me develop my question.
While this type of search is not good enough to be a final search strategy, it is a useful starting point. It should be sufficient to give you a rough idea of how much research there is on a topic, and what aspect of that topic you would like to consider in your systematic literature review.
A question framework is a tool to help you help you identify and clearly express the main concepts of your topic, which can then be turned into a focused research question.
There are a number of question frameworks available, here we have provided information and examples about 2 frameworks; PICO/PECO and PCC. You should chose the framework that suits your topic best.
Reviews of interventions, diagnostic tests, aetiology or risk, and cost effectiveness or economic evaluations can usually be framed using PICO/PECO. For new or emerging research topics you may have a less specific/narrow question. If you are finding it difficult to fit your topic into the PICO framework you may find PCC better suited.
Reviews of interventions, diagnostic tests, aetiology or risk, and cost effectiveness or economic evaluations can usually be framed using PICO/PECO.
| Initials | What should I write here? |
|---|---|
| P - population or problem | What group of people or condition are you interested in? |
|
I - intervention OR E - exposure |
What intervention is being applied to your population? OR What exposure should your population have had? |
| C - comparison or control |
Is there a specific comparison you would like to make to your intervention or exposure? |
| O - outcome | What outcome(s) are you interested in? |
Please see below for examples of how different question types can be framed with PICO/PECO.
How do delayed antibiotic prescriptions for respiratory infections affect patient and service outcomes?
| Initials | What should I write here? | Example |
|---|---|---|
| P - population or problem | What group of people or condition are you interested in? | Patients with respiratory infections |
|
I - intervention |
What intervention is being applied to your population? | Delayed antibiotic prescription |
| C - comparison or control | Is there a specific comparison you would like to make to your intervention? |
- |
| O - outcome | What outcome(s) are you interested in? | Time to recovery, repeat GP appointment, emergency hospitalisation, patient satisfaction... |
How accurate are rapid antigen tests for the diagnosis of COVID-19/SARS-CoV-2 when compared with PCR tests?
| Initials | What should I write here? | Example |
|---|---|---|
| P - population or problem | What group of people or condition are you interested in? | COVID-19/SARS-CoV-2 |
|
I - intervention |
What test is being applied to your population? | rapid antigen tests |
| C - comparison or control | Is there a specific comparison you would like to make to your intervention? |
PCR test |
| O - outcome | What outcome(s) are you interested in? | diagnostic accuracy |
In lower and middle income countries, are children who are regularly exposed to high levels of air pollution at greater risk of being diagnosed with cancer during childhood?
| Initials | What should I write here? | Example |
|---|---|---|
| P - population or problem | What group of people or condition are you interested in? | children in lower and middle income countries |
|
E - exposure |
What exposure should your population have had? | high levels of air pollution |
| C - comparison or control | Is there a specific comparison you would like to make to your intervention? |
|
| O - outcome | What outcome(s) are you interested in? | childhood cancer |
Are delayed antibiotic prescriptions for respiratory infections cost effective when compared with immediate or no prescription?
| Initials | What should I write here? | Example |
|---|---|---|
| P - population or problem | What group of people or condition are you interested in? | Patients with respiratory infections |
|
I - intervention |
What intervention is being applied to your population? | Delayed antibiotic prescription |
| C - comparison or control | Is there a specific comparison you would like to make to your intervention? |
Immediate or no prescription |
| O - outcome | What outcome(s) are you interested in? | Cost effectiveness |
Scoping review questions are generally better suited to the PCC framework.
| Initials | What should I write here? |
|---|---|
| P - population | What group of people or condition are you interested in? |
|
C - concept |
What aspect of the population group are you interested in learning more about? |
| C - context | What context or setting (e.g. primary care, low and middle income countries, etc) are you interested in? |
Below is an example of how a scoping question could be framed with PCC.
What are the barriers and facilitators to implementing delayed antibiotic prescription to patients with respiratory infections attending primary care?
| Initials | What should I write here? | Example |
|---|---|---|
| P - population | What group of people or condition are you interested in? | Patients with respiratory infections |
|
C - concept |
What aspect of the population group are you interested in learning more about? | Barriers / facilitators to implementing delayed antibiotic prescription |
| C - context | What context or setting (e.g. primary care, low and middle income countries, etc) are you interested in? | Primary Care |
Is there an existing systematic review that seeks to answer this question?
You should try to pick a novel question that has not already been answered. If you are concerned about potential overlap between your question and existing publications please discuss this with your supervisor or course team.
Is there enough literature on this topic to justify a systematic literature review?
It will be difficult to write a meaningful SLR if there are fewer than 5 relevant papers published on the topic. If this is the case you should consider broadening your research question.
Is there too much literature on this topic?
You may find it challenging to complete your SLR in the timeframe allocated for your masters dissertation if there are more than 25 relevant papers published on the topic. If this looks to be the case you should consider narrowing your research question.