The measure used to assess the success of any given assisted reproductive technology (ART) treatment is dependent upon whose perspective the outcome is being determined and the quality of the data available to populate the measure. The three most commonly used denominators to measure the success of ART treatment are initiated cycles, aspirations, and embryos transferred. Clinical pregnancy is the most widely used measure of the success of ART treatment. The choice of initiated cycle as the denominator is limited to differentiate the success rates between some ART procedures such as in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Cryopreservation of embryos is now routine practice. The dilemma is how to present success rates of ART treatment following transfer of thawed embryos. A higher success rate is also experienced with patients undertaking their first treatment cycle or who have a history of a live birth.