Covidence supports people asking various types of research questions.
When developing your research question, it's useful to consider the type of question you're asking. This focuses your question and determines the rest of your review design, including which framework best fits (e.g. PICO, PECO) and which study designs will best answer it. We’ve provided a brief description of some common question types below.
Effectiveness (intervention / treatment)
These questions aim to evaluate the effectiveness of different interventions (treatments, drugs, therapy, educational changes, social changes, etc) in improving some outcome(s).
Example: In patients with osteoarthritis of the knee, is hydrotherapy more effective than traditional physiotherapy in relieving pain?
Evidence Mapping
These questions aim to highlight patterns such as the distribution of research across populations, settings, interventions, outcomes, or study designs. This makes them useful for identifying where evidence is concentrated and where significant gaps exist, offering a foundation for future research or developing systematic reviews.
Example: What evidence is available on policies and interventions related to health and climate change in Australia?
Prevention
These questions aim to evaluate the effectiveness of an intervention or exposure in preventing morbidity and mortality.
Example: For obese children, does the use of community recreational activities reduce the risk of diabetes, compared with educational programmes?
Etiology (Harm / Causation)
These questions aim to evaluate the harmful effect of an intervention or exposure.
Example: Do adults who binge drink compared with those who do not binge drink have higher mortality rates?
Diagnosis
These questions aim to compare the accuracy and safety of diagnostic tests against the standard method.
Example: For deep vein thrombosis is D-dimer testing or ultrasound more accurate for diagnosis?
Prognosis (Forecast)
These questions aim to explore the likelihood of specific outcomes for patients with particular disorders.
Example: In healthy older women that suffer hip fractures within the year after injury, what is the relative risk of death?
Qualitative (Meaning)
These questions aim to synthesise qualitative evidence to address questions on aspects of interventions other than effectiveness.
Example: What are women's experiences of menopause?
Prevalence/incidence
These questions aim to estimate how common a condition, disease, or exposure is within a defined population, typically over a specified time period. Rather than evaluating the effectiveness of an intervention, these reviews summarise evidence from multiple studies to estimate how frequently a condition or exposure occurs.
Example: What is the incidence of postpartum depression among first-time mothers in low- and middle-income countries, and how does it vary by maternal age, delivery method, and access to postnatal care?
Methodology
These questions aim to examine, evaluate, or compare the research methods, designs, or reporting practices used across a body of literature, assessing how studies were conducted rather than synthesizing what they found.
Example: How do randomized controlled trials in physiotherapy research report and handle missing data, and to what extent do they follow CONSORT guidelines for missing data reporting?