title: [Cutoff scores of the Ages and Stages Questionnaire-Chinese for screening infants and toddlers].
abstract: OBJECTIVE
  To study the validity and accuracy of differing cutoff scores of the Ages and Stages Questionnaires-Chinese (ASQ-C) for screening infants and toddlers in comparison with the gold standard, Bayley Scale of Infant Development, Second Edition (BSID II).
  
  
  METHODS
  The 269 samples were enrolled from the normative children, aged 3 - 31 months, of the ASQ-C in Shanghai. The age-appropriate ASQ-Cs were completed by parents/caregivers and the BSIDIIwas administered by professionals. The cutoff scores of -2 standard deviation (s), -1.5 s, and -s for the ASQ-C were examined against BSID II with the cutoff scores set at -2 s as the standard of developmental delay, -s as the standard of suspected developmental delay and developmental delay respectively. Agreement between the classifications of the ASQ-C (i.e., typical, suspected, delay) was compared with the classification of the BSID II (typical, suspected, delay), sensitivity, specificity, Youden Index and area under ROC curve of ASQ-C were examined. The statistical analysis was carried out using SPSS 13.0.
  
  
  RESULTS
  When the cutoff score for BSID II was -2 s, the -2 s cutoff score for ASQ-C exhibited the following properties: the highest agreement of 83.64%, the sensitivity and specificity both above 80% being respectively 88.46% and 83.13%, the highest Youden Index of 0.72 and the largest area of 0.86 under ROC curve. The -1.5 s cutoff score for ASQ-C showed the following properties: 71.75% agreement, 100% sensitivity, 68.72% specificity, Youden Index = 0.69, the area under ROC curve = 0.84. The -s cutoff score for ASQ-C showed the following properties: the lowest agreement of 55.02%, 100% sensitivity, the lowest specificity of 50.21%, the lowest Youden Index of 0.50, and the smallest area of 0.75 under ROC curve. When the cutoff score for BSID II was set at -s, the -2 s for ASQ-C showed the following properties: the highest agreement of 85.87%, the lowest sensitivity of 68.57%, the highest specificity of 91.96%, Youden Index = 0.61, the smallest area = 0.77 under ROC curve. The -1.5 s for ASQ-C showed the following properties: the agreement of 80.67%, the sensitivity and specificity both above 70% being respectively 85.71% and 78.89%, the highest Youden Index of 0.65, the largest area of 0.82 under ROC. The -s cutoff score for ASQ-C showed the following properties: the lowest agreement of 68.40%, the highest sensitivity of 94.29%, the lowest specificity of 59.30%, the lowest Youden Index of 0.54, and the area under ROC curve = 0.80. When the cutoff score for BSID II was -1 to 2 s, the identifying percentages of the -2 s, -1.5 s and -s for the ASQ-C were 56.82%, 77.27% and 90.91%, respectively.
  
  
  CONCLUSIONS
  For developmental delay identification, the -2 s cutoff score for ASQ-C produces the most robust validity and highest accuracy; for the identification of suspected developmental delay and developmental delay, the -1.5 s cutoff score for ASQ-C has the highest screening accuracy with appropriate sensitivity and specificity; for identifying the suspected developmental delay, the -s cutoff score for ASQ-C has the highest percentage of the identification. It is necessary to add 1 - 2 s to the ASQ-C's cutoff scores as the standard for screening suspected developmental delays.
authors.affiliation: Shanghai Children's Health Care Institute, Shanghai Jiao Tong University, Shanghai 200040, China.
authors.forename: Guo-ying
authors.initials: GY
authors.lastname: Yao
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Bian
authors.forename: Jane
authors.initials: J
authors.lastname: Squires
authors.forename: Mei
authors.initials: M
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Song
mesh_terms: D002657:Child Development; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008403:Mass Screening; D012015:Reference Standards; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*