title: Comparison of parameters to study seasonality in reproductive outcome.
abstract: This report compares validity, precision and convenience of three frequently used parameters used to describe seasonality in reproductive outcome: prevalence, index and ratio observed versus expected. Each has its advantages and disadvantages; the choice of the parameter depends on the aim of the study. It is advisable to report the number of cases and referents per month, because all three parameters can be derived from this information.
mesh_terms: D001723:Birth Rate; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D015203:Reproducibility of Results; D012621:Seasons