title: Longitudinal Assessment of Examiner Experience and the Accuracy of Sonographic Fetal Weight Estimation at Term.
abstract: OBJECTIVE
  To evaluate the influence of examiner experience on the accuracy of sonographic weight estimation and to further analyze examiners' individual learning curves.
  
  
  METHODS
  In this multicenter study, 4613 sonographic weight estimations performed by 18 examiners at the beginning of their ultrasound training were included. To assess the effect of experience on the accuracy of weight estimation, a multivariable mixed regression model analysis was performed, with percentage error and absolute percentage error as outcome variables and the examiner, the examiner's experience (number of examinations), birth weight, gestational age, scan-to-delivery interval, and maternal body mass index as fixed effects and the perinatal center as random intercepts. To further analyze the individual learning curves of the examiners, the cumulative summation technique was used.
  
  
  RESULTS
  Regression analyses showed a significant influence of the number of examinations on the accuracy of sonographic weight estimation after adjustment for the above-mentioned parameters (P < .001). A typical learning curve with improving accuracy was found until approximately 200 examinations. Between 200 and 300 examinations, the diagnostic performance started to deteriorate again, with a continuous decrease until the end of the study period. Cumulative summation charts representing individual learning curves varied greatly between different examiners.
  
  
  CONCLUSIONS
  These findings indicate the great importance of continuous quality control systems in sonographic weight estimation.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Faschingbauer
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Heimrich
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Raabe
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Kehl
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Department of Medical Informatics, Biometry, and Epidemiology, Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Erlangen, Erlangen, Germany.
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Beckmann
authors.affiliation: Department of Medical Informatics, Biometry, and Epidemiology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Hepp
authors.affiliation: Department of Obstetrics and Perinatal Medicine, Perinatalzentrum Hannover, Diakonischen Dienste Hannover Frauenkliniken, Hannover, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Lübke
authors.affiliation: Department of Obstetrics and Perinatal Medicine, Perinatalzentrum Hannover, Diakonischen Dienste Hannover Frauenkliniken, Hannover, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mayr
authors.affiliation: Department of Obstetrics and Perinatal Medicine, Perinatalzentrum Hannover, Diakonischen Dienste Hannover Frauenkliniken, Hannover, Germany.
authors.forename: Ralf L
authors.initials: RL
authors.lastname: Schild
mesh_terms: D015992:Body Mass Index; D002983:Clinical Competence / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D005260:Female; D020567:Fetal Weight / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D015203:Reproducibility of Results; D012189:Retrospective Studies; D047929:Term Birth / Q000502:physiology; D016216:Ultrasonography, Prenatal / Q000379:methods*
keywords: birth weight; cumulative summation; examiner experience; fetal weight estimation; obstetric ultrasound; sonography