Searching systematically: literature searching in a systematic way

Is your question quantitative or qualitative? Different frameworks can help you define your question

Is your question relating to :

Epidemiology,  Diagnosis,  Therapy,  Prognosis,  Screening,  Treatment Benefits, Treatment Harms or Cost Effectiveness?

Knowing what type of question you want to answer will help you determine what type of research studies you will include in your literature review. Your chosen framework can also be used to develop your inclusion/exclusion criteria and organise your search terms (see search planning form in "Documenting your search" ).

Patient/Population/Problem: What are the patient's demographics? For example the patient's age, gender or ethnicity?  Or what type of problem is it? For example a disease, a medical condition?

Intervention/Exposure: What type of intervention is being considered? For example: type of medication, exercise program or rest? Or is it an exposure, for example: domestic violence, disease or disorder?

Comparison: (this part can be left out if no comparisons are being made): are you comparing the intervention/exposure to another treatment/exposure? Can it be treatment as normal or placebo or another specific intervention?

Outcomes: What is the desired effect? you would like to see? What effects are not wanted? Are there any side effects involved?

Study types: What study types will you include in your review? All types? Observational? Trials? Systematic reviews?

Not all parts of the PICO have to be used. Variations include:

• PIO (Patient/population/Intervention/Outcome
• PICOT (Patient/population/Intervention/Comparison/Outcome/Time)
• PICOCS (Patient/population/Intervention/Comparison/Context/Study types) 
• PEOS (Patient/population/exposure/outcomes/study types)
• PEOCS (Patient/population/Exposure/Outcomes/Context/Study types)

For example:

CLIP is often used for topics relating to health management, policies or economics.

Client – who is the service aimed at?
Location – where is the service located?
Improvement – what do you want to find out?
Professional – who is involved in providing/improving the service?

ECLIPSE is often used for topics relating to health management, economics or policies.

Expectation - what is the information needed for?
Client Group -who is the information needed for e.g. health managers, GPs, patients
Location - where is the client group or service located?
Impact - what change in the service, if any, is being looked for? What would constitute success? How is this being measured?
Professionals - what health professionals are involved in the service?
Service - for which service are you looking for information? For example, outpatient services, nurse-led clinics, intermediate care.

The SPIDER framework, is designed using the PICO tool as a starting point and is useful when developing search strategies for qualitative and mixed-methods research.

• Sample (S): What are the patient's demographics eg age, gender and ethnicity?  Or what type of problem is it?
• Phenomenon of Interest (PI): The how and why of certain behaviours, decisions, and individual experiences
• Design (D): What is the study design?
• Evaluation (E): What would be the desired effect you would like to see? What effects are not wanted? Attitudes and views?
• Research types (R): What study types will you include in your review? qualitative, quantitative, mixed methods?

For example:

CONCEPTS

If your topic or question does not fit into an existing framework, you can divide your question into concepts as it helps you to clarify the question and be able to search each concept separately. 

Systematic Review:  "a literature review that is designed to locate, appraise, and synthesize the best available evidence relating to a specific research question to provide informative and evidence-based answers."  Cherry, M.G., Boland, A., Dickson R. (eds)  (2024). Doing a Systematic Review, London, SAGE p2

Randomised Controlled Trial: Comparison between group of patients exposed to a treatment or intervention and a control group  (evaluates effectiveness of the intervention)

Cohort Study: Two groups of patients (cohorts) one of which has received the exposure being studied and the other not.  (measures incidence and cause of disease)

Case Control Study:  Set of patients with defining characteristic of interest is selected and compared with controlled group without characteristic.  (potential cause of disease) 

Case Report or Case Series:  Report on a single patient or a series of patients (recognition of a new disease or hypothesis)

James Cook University Australia.

Integrative Reviews - Defining the question frameworks. 

University of Maryland

Developing a research question - models and frameworks

Cochrane - example of a search strategy for a Cochrane Review completed in Medline (OVID).

Appendix 6 of the Cochrane Handbook