| Survey year 2018/2019a | Survey year 2019/2020b | Survey year 2020/2021c | |||||||
---|---|---|---|---|---|---|---|---|---|---|
 | N | % Delay | OR (95% CI) | N | % Delay | OR (95% CI) | N | % Delay | OR (95% CI) | |
Bivariate associations | ||||||||||
Sex | GirlsRef | 9,112 | 17.4 | - | 9,606 | 15.7 | - | 9,433 | 15.3 | - |
 | Boys | 10,187 | 24.4 | 1.53***(1.43–1.64) | 10,310 | 22.4 | 1.54***(1.44–1.66) | 10,265 | 22.0 | 1.56***(1.46–1.68) |
Age |  < 6.0 yearsRef | 12,224 | 21.5 | - | 12,316 | 19.7 | - | 11,098 | 20.1 | - |
 |  < 7.0 years | 6,941 | 19.9 | 0.90** (0.84–0.97) | 7,453 | 17.7 | 0.87***(0.81–0.95) | 8,411 | 16.6 | 0.79***(0.73–0.85) |
 |  > 7.0 years | 134 | 52.2 | 3.98***(2.80–5.71) | 147 | 51.7 | 4.36***(3.12–6.14) | 189 | 40.7 | 2.72***(2.00–3.69) |
Language | GermanRef | 18,111 | 20.2 | - | 18,642 | 18.2 | - | 18,221 | 17.8 | - |
 | other (mb) | 569 | 36.0 | 2.22***(1.86–2.66) | 753 | 35.2 | 2.44***(2.09–2.86) | 825 | 35.5 | 2.54***(2.19–2.95) |
 | bilingual | 619 | 34.9 | 2.11***(1.78–2.52) | 521 | 31.9 | 2.10***(1.74–2.54) | 652 | 25.5 | 1.57***(1.31–1.89) |
SEP index | highRef | 9,089 | 14.3 | - | 9,948 | 13.7 | - | 10,231 | 13.0 | - |
 | middle | 8,558 | 24.2 | 1.91***(1.77–2.07) | 8,416 | 21.4 | 1.71***(1.58–1.85) | 8,019 | 21.7 | 1.84***(1.71–2.00) |
 | low | 1,652 | 42.4 | 4.41***(3.93–4.94) | 1,552 | 42.5 | 4.66***(4.15–5.24) | 1,448 | 43.4 | 5.12***(4.54–5.77) |
Kindergarten |  < 4 yrsRef | - | - | 3,989 | 26.8 | - | 1,817 | 27.5 | - | |
 |  > 4 yrs | - | - | 15,927 | 17.3 | 0.56***(0.52–0.61) | 17,881 | 17.9 | 0.58***(0.52–0.64) | |
Multivariate logistic regression | ||||||||||
 | language[other (mb)] | - | 1.80***(1.49–2.16) | - | 1.83***(1.55–2.16) | - | 1.97***(1.67–2.32) | |||
 | SEP index[middle] | - | 1.97***(1.82–2.13) | - | 1.73***(1.60–1.87) | - | 1.89***(1.75–2.05) | |||
 | SEP index[low] | - | 4.23***(3.76–4.76) | - | 4.04***(3.58–4.55) | - | 4.71***(4.16–5.33) | |||
 | kindergarten[≥4 yrs] | - | - | - | 0.75***(0.68–0.81) | - | 0.85**(0.75–0.96) | |||
 |  | - | R2 Tjur | - | R2 Tjur | - | R2 Tjur | |||
 |  |  | 0.056 |  | 0.058 |  | 0.060 |