1. Controversies and Current Research The immune system in menopause and infertility Northside Hospital WomenFirst February 26, 2002 Mark Perloe, M.D., mpmd@ivf.com www.ivf.com
Assignment of individuals is randomized RCT: Individuals similar at the beginning RCOT: Prospective analytical, susceptible to bias if carry over effects occur Observational: allocation or assignement is not under investigator control; weaker potential evidence; potential for large confounding variables Cohort: prospective, follow-up period to determine effect of exposure and outcome, stronger than case-control but more expensive Case-Control: retrospective, secondary data from chart review, useful for rare conditions, inexpensive, many forms of bias Cross-Sectional: descriptive study of relationship between factors at one point in time Case-Series: series of cases, lack of comparability, source of hypothesis, most common study type Case-Report: anecdotal evidence,