Item reduction of the Wisconsin Upper Respiratory Symptom Survey (WURSS-21) leads to the WURSS-11

To develop a shorter version of the Wisconsin Upper Respiratory Symptom Survey (WURSS-21), a self-report questionnaire for evaluating daily symptoms and functional impairments during acute respiratory illness (ARI). WURSS-21 data were retrieved from 4 studies (n = 1167) spanning the years 2002-2010. Similar methodologies were employed among these studies. Degree of missingness, ceiling/floor effects, and exploratory (EFA) and confirmatory (CFA) factor analyses were investigated and used to guide item retention. Stability of the reduced WURSS was evaluated across the first 3 days of ARI. Degree of missingness was < 1 % and appeared to be completely at random. Seven WURSS items with > 30 % of ratings of zero (floor effects) were eliminated. Cross-loading items (head congestion, sleep well and breathe easily) were excluded following EFA on subset-1. Subsequent CFA using subset-2 showed satisfactory indices of fit. The reduced WURSS-11 instrument demonstrated 3 dimensions of 3 items each and was stable across 3 days of illness. The indicated dimensions (items) include nasal (runny nose, plugged nose, sneezing), throat (cough, sore throat, scratchy throat), and quality of life (feeling tired, think clearly, accomplish daily activities). The WURSS-11 has similar dimensional structure as the WURSS-21. This shorter version may reduce the time and burden required for completing the survey.