Inter/intra investigator variation in orchidometric measurements of testicular volume by ten investigators from five institutions.

Aim: To perform quality control studies on testicular volume measurements for a multi-center epidemiological study of male reproductive function.

Methods: We constructed a data matrix with a balanced assignment for 2 consecutive days by ten investigators (andrological career: 4-21 years) from five institutions and 12 male volunteers aged 20-26 years. Testicular volume was measured by Prader's orchidometer.