RT Journal Article SR Electronic T1 Retrospective Studies and Chart Reviews JF Respiratory Care FD American Association for Respiratory Care SP 1171 OP 1174 VO 49 IS 10 A1 Hess, Dean R YR 2004 UL http://rc.rcjournal.com/content/49/10/1171.abstract AB A retrospective study uses existing data that have been recorded for reasons other than research. A retrospective case series is the description of a group of cases with a new or unusual disease or treatment. With a case-control study, cases with and without the condition of interest are identified, and the degree of exposure to a possible risk factor is then retrospectively compared between the 2 groups. With a matched case-control study, control subjects are selected such that they resemble (match) the cases with regards to certain characteristics (eg, age, comorbidity, severity of disease). Retrospective study designs are generally considered inferior to prospective study designs. Therefore, a retrospective study design should never be used when a prospective design is feasible.