title: Cross-sectional reporting of previous Cesarean birth was validated using longitudinal linked data.
abstract: OBJECTIVE
  The aim of this study was to demonstrate the feasibility of using linked health records to assess data quality in population health data.
  
  
  METHODS
  Reproductive histories of 155,897 women were constructed by longitudinal linkage of the New South Wales (Australia) birth records in 1998-2005, and 127,952 birth and hospital discharge records in 2000-2005 were cross-sectionally linked. History of Cesarean section (CS) derived from the longitudinal linkage ("gold standard") was used to validate the CS history fields (i.e., "Was the last birth by Cesarean section?" and "Total number of previous Cesarean sections?") in birth records and to validate "vaginal birth after previous Cesarean (VBAC)" and "maternal care for uterine scar" in hospital records.
  
  
  RESULTS
  The reporting of CS at last birth was reliable with sensitivity, specificity, positive predictive value (PPV), and negative predictive value all >95% as was the number of previous CS (weighted kappa=0.97). For the hospital data, sensitivity and PPV were 46% and 99% for VBAC, 92% and 99% for maternal care of uterine scar, and 85% and 99%, respectively, for any prior CS.
  
  
  CONCLUSIONS
  Assessing data quality by record linkage is feasible and can be done more quickly and cheaply than by any traditional validation study.
authors.affiliation: Clinical and Population Perinatal Health Research, The Kolling Institute of Medical Research, University of Sydney, New South Wales, Australia. jschen@med.usyd.edu.au
authors.forename: Jian Sheng
authors.initials: JS
authors.lastname: Chen
authors.forename: Christine L
authors.initials: CL
authors.lastname: Roberts
authors.forename: Jane B
authors.initials: JB
authors.lastname: Ford
authors.forename: Lee K
authors.initials: LK
authors.lastname: Taylor
authors.forename: Judy M
authors.initials: JM
authors.lastname: Simpson
mesh_terms: D017604:Cesarean Section, Repeat / Q000706:statistics & numerical data*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008498:Medical Record Linkage / Q000592:standards; D009517:New South Wales; D011247:Pregnancy; D015203:Reproducibility of Results; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data