Is the study design appropriate?
Appropriate Study Design
Does this treatment work?
Systematic review or meta-analysis of trials; RCT
How good is a diagnostic test?
(Prospective) cohort study; systematic review of cohort studies
Should we screen?
RCT; systematic review of trials
What causes this disease?
RCT; prospective cohort study; case-control study (rare diseases); systematic review
What did people think or do?
Cohort study; cross-sectional survey; qualitative study
Advice on whether a study is correctly termed prospective or retrospective can be found in this BMJ paper.
Suboptimal study designs include:
- case series with no (or inadequate) control group. We will consider these if they are sufficiently informative and are compelling and well described. A suitable instance may be to describe early management of a major threat to public health.
- retrospective study using casenotes, charts, or other routinely collected records in one or only a few hospital/general practice/doctor’s office(s). We will consider these if the records were interrogated to answer a clear, predefined research question and the database included over 400 patients’ details.
- non-randomised trial of a comparison or intervention/uncontrolled intervention study. We may consider such an article, however, if it reports the evaluation of a quality improvement initiative where the rationale and process evaluation may have been more important than the outcomes; a large scale public health or health services intervention; or a “journalology”/peer review research study where randomisation was impossible.