Retrospective Studies The outcome of interest has already occurred by the time of enrollment in the study. Data are collected either from records or by asking participants to recall exposures. There is no follow-up of participants.
Prospective Studies The outcome (and sometimes the exposure or intervention) has not occurred when the study begins. Participants are followed up over a period of time to observe outcomes.
Most cohort studies are prospective studies (though there may be retrospective cohorts), whereas case–control studies are retrospective studies. An interventional study is a prospective study since the investigator determines the exposure for each study participant and follows them to observe outcomes (Ranganathan et al., 2018).
Per Nickson (2019), retrospective studies are designed to analyze pre-existing data and may be subject to numerous biases. Retrospective studies may be based on chart reviews (data collection from the medical records of patients). Types of retrospective studies include:
Research studies often contain language that may be unfamiliar to nurses. Per Chrisman et al., (2014) some of the basic terminology commonly found in research studies are:
Study Designs - Centre for Evidence-Based Medicine. This short article from the Centre for Evidence-Based Medicine, University of Oxford, gives a brief guide to the different study types and a comparison of the advantages and disadvantages.