Table 1.

Characteristics of survey participants

		Year of survey
		2018/2019 Pre-pandemic		2019/2020 Pandemic start		2020/2021 Pandemic
N		23,997		24,850		24,788
		N	%	N	%	N	%
Sex	Girls	11,322	47.2	11,867	47.7	11,758	47.4
	Boys	12,675	52.8	12,983	52.3	13,030	52.6
Age	≤ 6.0 years	15,077	62.9	15,049	60.6	13,729	55.4
	< 7.0 years	8,689	36.2	9,550	38.4	10,753	43.4
	> 7.0 years	231	0.96	251	1.0	306	1.2
SEP index	High	9,853	41.1	10,802	43.5	10,966	44.3
	Middle	9,473	39.4	9,277	37.3	8,756	35.3
	Low	2,050	8.5	1,930	7.7	1,766	7.1
	Missing information	2,621	10.9	2,841	11.4	3,300	13.3
Native language	German	21,308	88.8	22,055	88.7	21,542	86.9
	Other (mb)	1,236	5.2	1,338	5.4	1,559	6.3
	Bilingual	884	3.7	770	3.1	896	3.6
	Missing information	569	2.4	687	2.8	791	3.2
Kindergarten	< 4 years	n.a	n.a	4,789	19.3	2,362	9.5
	> 4 years	n.a	n.a	17,285	69.6	19,927	80.4
	Missing information	n.a	n.a	2,776	11.2	2,499	10.1

n.a. not available (In 2018/2019, the ‘kindergarten’ variable was operationalised differently than in 2019/2020 and 2020/2021.); mb migration background, SEP socioeconomic position