Table 2.
Baseline Questionnaire Reliability and Validity
| |
|
Internal consistency within domain |
% Agreement between two questionnaires |
Question and domain validity versus physician diagnosis |
||
|---|---|---|---|---|---|---|
| Phase II primary questionnaire domains scores (score range) | # Contributing questions/ symptoms | Cronbach's alpha | Spearman correlation | Spearman correlation | + Diagnosis median (Q1,Q3) | − Diagnosis median (Q1,Q3) |
| Asthma history score (0–7) | 7 | 0.90 | 0.94** | 0.82** | 6.0 (4.5,7.0) | 0.0 (0.0, 2.0) |
| Respiratory symptoms score (0–16) | 4 | 0.75 | 0.83** | 0.83** | 7.0 (4.0, 8.0) | 3.0 (1.0, 4.0) |
| Wheeze (0–4) | 1 | – | 0.92** | 0.48* | 1.0 (1.0, 2.0) | 0.0 (0.0, 1.0) |
| Cough (0–4) | 1 | – | 0.75** | 0.36* | 2.0 (1.0, 3.0) | 1.0 (0.0, 2.0) |
| Shortness of breath (0–4) | 1 | – | 0.82** | 0.46* | 2.0 (1.5, 3.0) | 0.0 (0.0, 1.0) |
| Chest tightness (0–4) | 1 | – | 0.88** | 0.57* | 1.0 (0.0, 2.0) | 0.0 (0.0, 0.0) |
| Allergic rhinitis symptoms score (0–5) | 5 | 0.88 | 0.43* | 0.25 | 4.0 (4.0, 5.0) | 4.0 (2.0, 5.0) |
| Atopic dermatitis score (0–9) | 3 | 0.92 | 0.84** | – | – | – |
| Family allergic disease score (0–12) | 12 | 0.69 | 0.88** | – | – | – |
| Tobacco smoke exposure score (0–8) | 8 | 0.71 | 0.90** | – | – | – |
Twenty caregivers of asthmatics and 20 caregivers of nonasthmatics were asked to complete two baseline questionnaires (the 14-page New Patient Visit Questionnaire and the eight-page New Visit Questionnaire). One questionnaire was completed prior to their clinic visit and a 2nd during their visit. Sample size for each individual questionnaire domain or symptom may vary due to incomplete or missing data. See Table 2 for questions that make up each domain. Internal consistency within a single questionnaire was measured using the Cronbach's alpha statistic. Reliability between questionnaires and validity versus the physician diagnosis was measured using the Spearman correlation coefficient given the data were not normally distributed. +/− Diagnosis indicates the presence or absence of an asthma diagnosis for the Asthma History and Respiratory Symptoms Domain Scores and allergic rhinitis diagnosis for the Allergic Rhinitis Symptoms Domain Scores; Q1=25th percentile; Q3=75th percentile; *p<0.05; **p<0.001; – indicates the statistic was not computed.