Analytic methods for assessing the results of infertility therapy are reviewed and deficiencies discussed. A classification and staging scheme to define the type and severity of infertility problems is needed. Once homogeneous groups of patients are defined, the results of infertility therapy can be documented by the life-table method of analysis. A detailed description and format for this type of analysis are presented. To help conceptualize statistical probability as it pertains to infertility data, we have borrowed a mathematical model of fertility from demographers. This model can be used to predict the cumulative probability of conception over time, given a certain monthly probability of conception or fecundability. Also given that a couple has a certain duration of infertility, the model can be used to provide an estimate of an upper limit of the couple's likely monthly fecundability.