title: Inter/intra investigator variation in orchidometric measurements of testicular volume by ten investigators from five institutions.
abstract: OBJECTIVE
  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. A skilled technician also performed an ultrasound estimate of testicular volume.
  
  
  RESULTS
  A statistically significant inter-investigator variation was found for both testes (P < 0.05). In addition, there was a statistically significant investigator-by-volunteer interaction in testicular volume measurement (P < 0.01). However, there was no statistically significant difference in the two measurements performed on consecutive days for either testis. The testicular volumes for both the right and left testes as estimated by ultrasonography were smaller than results using the orchidometer. However, there was no statistical significance (P > 0.05). The difference in experiences of the investigators did not significantly correlate with accuracy of measurements in either testis.
  
  
  CONCLUSIONS
  The present study revealed significant differences in the results of estimation of testicular volume among the ten investigators, but intra-investigator variation was not considerable. Improved training and proper standardization of the measurement will be necessary before starting a multi-center study based on an andrological examination.
authors.affiliation: Unit of Medical Statistics, Faculty of Medical Education and Culture, St. Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Tatsunami
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Matsumiya
authors.forename: Akira
authors.initials: A
authors.lastname: Tsujimura
authors.forename: Naoki
authors.initials: N
authors.lastname: Itoh
authors.forename: Takumi
authors.initials: T
authors.lastname: Sasao
authors.forename: Eitetsu
authors.initials: E
authors.lastname: Koh
authors.forename: Yuuji
authors.initials: Y
authors.lastname: Maeda
authors.forename: Jiro
authors.initials: J
authors.lastname: Eguchi
authors.forename: Kousuke
authors.initials: K
authors.lastname: Takehara
authors.forename: Takayasu
authors.initials: T
authors.lastname: Nishida
authors.forename: Satetsu
authors.initials: S
authors.lastname: Miyano
authors.forename: Chisato
authors.initials: C
authors.lastname: Tabata
authors.forename: Teruaki
authors.initials: T
authors.lastname: Iwamoto
mesh_terms: D000328:Adult; D033441:Andrology; D006801:Humans; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D013737:Testis / Q000033:anatomy & histology*