Table 4—

Potential impact of incorrect answers on the results of this prevalence survey by three different scenarios#

Observed prevalencePrevalence by scenario
ABC
All children13.210.025.211.9
By ethnic group
 White13.210.121.211.4
 South Asian13.510.038.314.2
By Townsend index
 Least-deprived third12.99.619.910.8
 Middle third11.99.223.110.7
 Most-deprived third15.812.335.116.1
  • Data are presented as %. Scenario A: assumes 0% true prevalence in those who incorrectly understood wheeze but did not report wheezing children (prevalence = true-positives (TP)/n). Scenario B: assumes 100% true prevalence in those who incorrectly understood wheeze but did not report wheezing children (prevalence = (TP+potential false negatives (PFN)/n). Scenario C: assumes that the prevalence calculated in those who correctly defined wheeze applies to those who understood wheeze incorrectly and did not report wheeze (prevalence  =  (TP/n)+PFN×(TP/(TP + true-negatives))/n). #: assuming different proportions of false-negative reports in children of parents who incorrectly understood wheeze.