Table 1 Characteristics of the study sample

Demographic

Age (years)

13

28.4 (321)

33.5 (359)

13.6 (150)

14.3 (127)

59.7 (611)

53.6 (550)

14

43.1 (488)

35.6 (382)

41.8 (462)

44.8 (399)

34.9 (357)

37.1 (381)

15

28.5 (323)

30.9 (332)

44.6 (493)

40.9 (364)

5.5 (56)

9.3 (95)

Family structure

Intact

70.7 (800)

70.7 (759)

66.4 (730)

64.3 (571)

31.3 (320)

36.2 (371)

Restructured

11.1 (126)

9.5 (102)

5.8 (64)

5.5 (49)

18.1 (185)

17.5 (179)

Single parent

16.5 (187)

17.2 (185)

24.2 (266)

24.9 (221)

39.6 (405)

36.4 (373)

Other

1.7 (19)

2.5 (27)

3.6 (40)

5.3 (47)

11.1 (114)

10.0 (103)

Parental education

Low

43.8 (496)

42.1 (452)

29.9 (330)

31.2 (278)

54.0 (553)

51.9 (532)

High

46.4 (525)

46.6 (500)

48.7 (538)

46.1 (410)

29.4 (301)

31.2 (320)

Missing

9.8 (111)

11.3 (121)

21.5 (237)

22.7 (202)

16.6 (170)

17.0 (174)

Household size

2

5.5 (62)

6.0 (64)

10.6 (114)

8.6 (73)

5.7 (58)

5.3 (53)

≥3

94.5 (1062)

94.0 (1004)

89.4 (963)

91.5 (781)

94.3 (953)

94.7 (952)

Parenting

Parental warmth^a

Mean (SD); n

16.6 (3.1); 1107

15.7 (3.1); 1032

16.2 (3.3); 1021

15.5 (3.2); 792

17.0 (3.5); 960

16.6 (3.5); 908

Parental involvement^a

Mean (SD); n

17.2 (3.4); 1102

16.6 (3.3); 1041

17.6 (3.6); 1010

16.9 (3.6); 753

17.9 (4.1); 937

17.0 (4.1); 891

Inconsistent parenting^a

Mean (SD); n

11.8 (3.4); 1101

11.8 (3.3); 1044

12.1 (3.3); 1022

11.8 (3.5); 803

12.6 (3.7); 902

12.4 (3.5); 881

Friendship ties

Number of close friends

0

1.3 (15)

1.8 (19)

3.3 (36)

1.9 (17)

1.9 (19)

2.6 (26)

≥1

98.7 (1104)

98.2 (1042)

96.7 (1048)

98.1 (862)

98.1 (991)

97.5 (993)

Personal characteristics

I am shy

Not True

47.7 (534)

57.3 (606)

39.4 (427)

38.7 (327)

39.7 (392)

56.0 (534)

Somewhat true

38.2 (428)

36.2 (383)

43.5 (472)

47.6 (402)

37.0 (365)

30.0 (286)

Certainly true

14.1 (158)

6.4 (68)

17.1 (186)

13.7 (116)

23.3 (230)

14.0 (133)

School-based factors

School attachment (I like school)

Not true

47.5 (536)

61.1 (654)

27.3 (300)

40.5 (356)

33.2 (337)

40.6 (412)

True

52.5 (593)

38.9 (417)

72.7 (800)

59.6 (524)

66.8 (677)

59.4 (603)

Peer victimisation^a

Mean (SD); n

3.6 (3.9); 1093

3.9 (4.5); 1030

4.0 (4.3); 1042

5.3 (5.5); 803

5.1 (5.0); 958

5.6 (6.0); 913