Table 1

Summary of 2011, 2012 and 2013 data for the 1035 participants with linked responses

Variable2011 (n, %)2012 (n, %)2013 (n, %)
Sex
 Boy503 (48.6)503 (48.6)503 (48.6)
 Girl532 (51.4)532 (51.4)532 (51.4)
Age
 11147 (14.2)
 12416 (40.2)147 (14.2)
 13379 (36.6)434 (41.9)105 (10.1)
 1490 (8.7)365 (35.3)406 (39.2)
 1588 (8.5)420 (40.6)
 16101 (9.8)
 Missing3 (0.3)1 (0.1)3 (0.3)
Deprivation quintile
 1 (least deprived)314 (30.3)338 (32.7)287 (27.6)
 2107 (10.3)115 (11.1)101 (9.7)
 3180 (17.4)201 (19.4)165 (15.9)
 4157 (15.2)181 (17.5)160 (15.4)
 5 (most deprived)132 (12.8)151 (14.6)130 (12.5)
 Missing145 (14.0)49 (4.7)197 (18.9)
Parental smoking
 Neither parent smokes743 (71.8)749 (72.4)758 (73.2)
 One parent smokes192 (18.6)188 (18.2)202 (19.5)
 Both parents smoke90 (8.7)76 (7.3)71 (6.9)
 Missing10 (1.0)22 (2.1)4 (0.4)
Sibling smoking
 None smokes963 (92.6)928 (89.2)934 (89.8)
 At least one smokes67 (6.4)90 (8.7)101 (9.7)
 Missing10 (1.0)22 (2.1)5 (0.5)
Smoking in the main family home
 Not allowed870 (84.1)893 (86.3)896 (86.6)
 Allowed155 (15.0)121 (11.7)134 (13.0)
 Missing10 (1.0)21 (2.0)5 (0.5)
Number of smoking friends
 None618 (59.7)368 (35.6)306 (29.6)
 One or two115 (11.1)153 (14.8)181 (17.5)
 Three or more94 (9.1)233 (22.5)290 (28.2)
 Not sure196 (19.0)258 (24.9)250 (24.2)
 Missing12 (1.2)23 (2.2)8 (0.8)
Self-perceived academic performance
 Excellent or good830 (80.2)794 (76.7)781 (75.5)
 Average or below average185 (17.9)220 (21.3)249 (24.1)
 Missing20 (1.9)21 (2.0)5 (0.5)
Rebelliousness
 Low592 (57.2)593 (57.3)619 (59.8)
 High420 (40.6)395 (38.2)390 (37.7)
 Missing23 (2.2)47 (4.5)26 (2.5)
Susceptibility to smoking
 Non-susceptible never-smoker802 (77.5)650 (62.8)572 (55.3)
 Susceptible never-smoker186 (18.0)250 (24.2)249 (24.1)
 Ever-smoker47 (4.5)135 (13.0)214 (20.7)
Notice cigarettes on displays in large shops
 Sometimes or less401 (38.7)388 (37.5)524 (50.6)
 Most times or every time617 (59.6)609 (58.8)473 (45.7)
 Missing17 (1.6)38 (3.7)38 (3.7)
Notice cigarettes on displays in small shops
 Sometimes or less259 (25.0)210 (20.3)290 (28.0)
 Most times or every time745 (72.0)774 (74.8)697 (67.3)
 Missing31 (3.0)51 (4.9)48 (4.6)
Frequency of visiting large shops
 Less than 2 or 3 times a week360 (34.8)356 (34.4)344 (33.2)
 At least 2 or 3 times a week667 (64.4)669 (64.6)689 (66.6)
 Missing8 (0.8)10 (1.0)2 (0.2)
Frequency of visiting small shops
 Less than 2 or 3 times a week485 (46.9)493 (47.6)435 (42.0)
 At least 2 or 3 times a week540 (52.2)535 (51.7)598 (57.8)
 Missing10 (1.0)7 (0.7)2 (0.2)
Number of brands recognised
 None282 (27.3)232 (22.4)227 (21.9)
 1–5 brands381 (36.8)362 (35.0)365 (35.3)
 More than 5 brands239 (23.1)346 (33.4)356 (34.4)
 Missing133 (12.9)95 (9.2)87 (8.4)