Table 3.
Agreement of questionnaire one and two with weighted κ values for ordinal scales answers and unweighted if answers are on or interpreted as nominal scale (inclusion of “I don’t know” and missing values). Participants with a relevant disease episode between questionnaire one and two are excluded for disease- and symptom-based items as well as antibiotic intake
| Item | Answer categories on ordinal scale (0– “ 4 times”) |
Answer categories on or interpreted as nominal scale (incl. “Don’t know” and missings) | ||||
|---|---|---|---|---|---|---|
| n |
Linear weighted agreement [%] |
Linear weighted Kappa and 95 % - confidence interval | n |
Non-weighted agreement [%] (Bennet’s S) |
Non-weighted k and 95 % - confidence interval | |
| Disease-based itemsa | ||||||
| URT infections (IN1) | 72 | 92.7 | 0.77 [0.67–0.86] | 75 | 73.3 (0.69) | 0.65 [0.53–0.77] |
| Visit to GP or outpatient department (IN1a) | – | – | – | 74 | 90.5 (0.87) | 0.75 [0.62–0.90] |
| Hospitalisation (IN1b) | – | – | – | 74 | 97.3 (0.96) | 0 [n.c.] |
| LRT infections (IN2) | 73 | 97.9 | 0.84 [0.67–0.92] | 75 | 89.3 (0.88) | 0.70 [0.49–0.83] |
| Visit to GP or outpatient department (IN2a) | – | – | – | 73 | 87.7 (0.84 | 0.50 [0.18–0.75] |
| Hospitalisation (IN2b) | – | – | – | 73 | 89.0 (0.85) | 0.16 [-0.01–0.37] |
| GIT infections (IN3) | 72 | 93.7 | 0.73 [0.57–0.87] | 75 | 76.0 (0.72) | 0.59 [0.46–0.75] |
| Visit to GP or outpatient department (IN3a) | – | – | – | 73 | 91.8 (0.89) | 0.57 [0.22–0.83] |
| Hospitalisation (IN3b) | – | – | – | 73 | 94.5 (0.93) | −0.02 [-0.06–0] |
| Lip herpes (IN4) | 73 | 98.6 | 0.87 [0.69–0.97] | 75 | 92.0 (0.91) | 0.75 [0.58–0.90] |
| Infections of skin or mucosa (IN5) | 73 | 98.3 | 0.65 [0.20–0.94] | 75 | 93.3 (0.92) | 0.42 [0.09–0.65] |
| Bladder infection (IN6) | 73 | 99.0 | 0.83 [0.69–0.93] | 75 | 94.7 (0.94) | 0.74 [0.50–0.89] |
| Kidney infection (IN7) | 72 | 99.7 | 0.86 [0.85–0.86] | 74 | 95.9 (0.95) | 0.24 [0.16–0.40] |
| Symptom-based itemsa | ||||||
| Cough (F1) | 72 | 97.2 | 0.77 [0.52–0.95] | 75 | 89.3 (0.88) | 0.67 [0.47–0.84] |
| Fever (F2) | 71 | 98.2 | 0.77 [0.60–0.93] | 75 | 88.0 (0.86) | 0.59 [0.44–0.78] |
| Diarrhoea (F3) | 72 | 97.2 | 0.90 [0.81–0.96] | 75 | 86.7 (0.84) | 0.77 [0.65–0.89] |
| Self-assessed comparison to peers | ||||||
| URT infections (IH1) | 86 | 91.0 | 0.68 [0.57–0.79] | 87 | 65.5 (0.59) | 0.52 [0.39–0.67] |
| LRT infections (IH2) | 87 | 94.0 | 0.74 [0.62–0.84] | 87 | 78.2 (0.74) | 0.67 [0.55–0.79] |
| GIT infections (IH3) | 87 | 92.5 | 0.70 [0.57–0.80] | 87 | 71.3 (0.66) | 0.58 [0.42–0.71] |
| Bladder and kidney infection (IH4) | 85 | 94.7 | 0.77 [0.62–0.86] | 87 | 80.5 (0.77) | 0.69 [0.56–0.81] |
| Infections of skin or mucosa (IH5) | 87 | 94.0 | 0.69 [0.52–0.81] | 87 | 80.5 (0.77) | 0.66 [0.49–0.77] |
| Other | ||||||
| Use of antibioticsa (A1) | 72 | 96.2 | 0.78 [0.66–0.89] | 74 | 83.8 (0.81) | 0.70 [0.55–0.84] |
| Influenza vaccination (V1) | – | – | – | 88 | 92.0 (0.89) | 0.84 [0.73–0.93] |
URT upper respiratory tract; LRT lower respiratory tract; GIT gastrointestinal tract; n.c. cannot be calculated
aOnly participants with no infectious disease episode between both questionnaires are included