title: Cumulative sum (CUSUM) analysis in the assessment of trainee competence in fetal biometry measurement.
abstract: OBJECTIVE
  To determine the value of cumulative sum (CUSUM) analysis in assessing trainee proficiency in fetal biometry measurement.
  
  
  METHODS
  Three primary healthcare doctors with no prior ultrasound training were recruited. Each trainee measured the fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) on 100 consecutive pregnant women. The supervisor repeated the measurements. The CUSUM for each set of trainee measurements was calculated at a set failure rate of 10%. The point at which the graph fell below two consecutive boundary lines indicated the number of examinations required to achieve competence.
  
  
  RESULTS
  The CUSUM graphs showed that the rate of learning measurement skills varied among the three trainees. The graph for the CUSUM series for BPD and HC measurement for all trainees fell below two consecutive boundary lines and remained there, indicating competence. The CUSUM series for AC measurement for two of the trainees indicated that competence was achieved; however, for the third trainee, while the graph fell below two consecutive boundary lines, indicating competence, it rose again, crossing two consecutive boundary lines. This indicated a loss of competence and the need for further training. FL measurements for the same trainee never fell below two consecutive boundary lines, indicating failure to achieve competence; the other two achieved competence, but failed to maintain it.
  
  
  CONCLUSIONS
  CUSUM is a useful tool for identifying points of competence and for quantifying the duration of ultrasound training required for each trainee. It provides an early indication of performance, and highlights difficulties in individual performance.
authors.affiliation: Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates University, Al Ain, United Arab Emirates.
authors.forename: S
authors.initials: S
authors.lastname: Weerasinghe
authors.forename: H
authors.initials: H
authors.lastname: Mirghani
authors.forename: A
authors.initials: A
authors.lastname: Revel
authors.forename: F M
authors.initials: FM
authors.lastname: Abu-Zidan
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging / Q000196:embryology; D001699:Biometry; D002983:Clinical Competence / Q000592:standards*; D004503:Education, Medical, Graduate; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000196:embryology; D047109:Fetal Development; D005333:Fetus / Q000196:embryology*; D005865:Gestational Age; D006257:Head / Q000000981:diagnostic imaging / Q000196:embryology; D006801:Humans; D010820:Physicians / Q000592:standards; D011247:Pregnancy; D011320:Primary Health Care; D011446:Prospective Studies; D011786:Quality Control; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000592:standards; D014479:United Arab Emirates