Description of sample before and after smoke-free legislation in Scotland. Values are numbers (percentages) unless stated otherwise
| Characteristic | 2006 (n=2532) | 2007 (n=2389) |
| Mean age (y) | 11.5 | 11.4 |
| Boys | 1289 (50.9) | 1227 (51.4) |
| Family affluence scale* | ||
| Low | 803 (32.8) | 739 (32.7) |
| Medium | 825 (33.7) | 763 (33.8) |
| High | 817 (33.4) | 756 (33.5) |
| Family socioeconomic classification*: | ||
| 1: Professional & managerial & technical | 795 (32.6) | 754 (33.2) |
| 2: Skilled non manual/ skilled manual | 773 (31.7) | 654 (28.8) |
| 3: Part skilled/unskilled | 237 (9.7) | 234 (10.3) |
| 4: Economically inactive¶ | 435 (17.8) | 438 (19.3) |
| Other† | 199 (8.2) | 191 (8.4) |
| Cotinine confirmed smoking status‡: | ||
| Non-smokers | 2339 (92.3) | 2217 (92.8) |
| Smokers | 46 (1.8) | 35 (1.5) |
| Missing§ | 147 (5.8) | 137 (5.7) |
| Family structure: | ||
| Both parents | 1723 (68.0) | 1602 (67.1) |
| Parent and step parent | 240 (9.5) | 229 (9.6) |
| Single mother | 453 (17.9) | 432 (18.1) |
| Single father | 45 (1.8) | 41 (1.7) |
| Other** | 36 (1.4) | 35 (1.5) |
| Unclassifiable | 17 (0.7) | 33 (1.4) |
| Missing | 18 (0.7) | 17 (0.7) |
↵* Pupils who reported living in both parent, step or single parent families only.
↵† Includes children whose family socioeconomic status was categorised as ‘Army’, ‘inadequately described’ and ‘not stated’
↵‡ Non-smokers=self-reported non-smokers with cotinine concentrations ≤15 ng/ml; smokers=cotinine concentrations >15 ng/ml regardless of self-reported smoking status.
↵§ Pupils who did not answer the smoking question or have a cotinine concentration assigned to them by the laboratory.
↵¶ Pupils who reported either that both parents did not have a job or if the only information available was on one parent who did not have a job.
↵** Pupils who reported to be living in a foster home or children's home or some other arrangement.