What is a Non-Randomised Intervention Study?
A Non-Randomised Intervention Study is a quantitative study investigating the effectiveness of an intervention that does not use randomisation to allocate patients (or units) to treatment groups. Non-randomised studies include observational studies, where allocation to groups occurs through usual treatment decisions or people's preferences. Non-randomised studies can also be experimental, where the investigator has some degree of control over the allocation of treatments. Non-randomised intervention studies can use a number of different study designs, and include cohort studies, case control studies, controlled before-and-after studies, interrupted-time-series studies and quasi-randomised controlled trials.