Defining a research question

Research questions versus review questions

A “research topic” is the area of study that you are researching, while a “review question” is the more focused question that your systematic review aims to answer. Depending on your starting point, you may arrive at a review question in different ways.

If you are working in an Applied Sciences field, or as a clinician, your review question might be informed by a problem or a scenario encountered in the laboratory or in practice.

If you are working towards your PhD, your thesis topic will be much broader than a question for a systematic review. To account for the many topics covered in your thesis, you may need to consider conducting a scoping review instead (see Preparing to start). For example, if your thesis explores non-therapeutic dementia treatments:  

  • a scoping review could identify all existing treatments

  • a systematic review might focus on the effectiveness of only one treatment.

Research mnemonics

Mnemonic devices help you remember things through simple tricks or associations. These tricks include acronyms, rhymes or images that connect information and ideas, making them easier to recollect.

Research mnemonics, like PICO, are acronyms used to write clinical questions and search databases. Each letter of the mnemonic represents a different concept important to your question. These concepts are then used to structure your database searches. 


The most widely used mnemonic for systematic reviews is PICO.

  • Population

  • Intervention

  • Comparator

  • Outcomes.  

Use PICO to formulate a research question in any field where the objective is to assess the effectiveness of an intervention.

Clinicians commonly use PICO in evidence-based practice, to determine the best way to treat a patient’s condition.  

Limitations of PICO

  • Contact

    For more help preparing for your systematic review, talk to library staff.

    Contact a librarian