Table 3.
Internal consistency of measurement scales
| Measure | Physical activity | Eating | ||
|---|---|---|---|---|
| No. of items | α | No. of items | α | |
| Perceived competence | 5 | .87 | 7 | .87 |
| Decision making (pros) | 9 | .91 | 4 | .82 |
| Decision making (cons) | 3 | .80 | 5 | .77 |
| Action control | 5 | .91 | 6 | .88 |
| Action planning | 4 | .95 | 4 | .89 |
| Habits | 12 | .97 | 11 | .96 |
| Subjective norms | 5 | .73 | – | – |
| Injunctive norms | – | – | 3 | .85 |
| Descriptive norms | – | – | 3 | .65 |
| Social support | 10 | .92 | – | – |
| Social support (negative) | – | – | 4 | .84 |
| Social support (positive) | – | – | 3 | .87 |
| Perceived environment (PA) | 5 | .85 | – | – |
| Perceived environment (home) | – | – | 4 | .78 |
| Perceived environment (shop) | – | – | 3 | .76 |
| Perceived environment (work) | – | – | 3 | .82 |
| Identity | 9 | .95 | 3 | .77 |
| Self-efficacy | 3 | .90 | 3 | .87 |
| PBC | 3 | .87 | 3 | .85 |
| Attitudes (instrumental) | 3 | .89 | 3 | .80 |
| Attitudes (affective) | 3 | .89 | 3 | .89 |
| Intentions | 3 | .96 | 5 | .91 |
| Goals (social) | 4 | .93 | – | – |
| Goals (appearance) | 3 | .95 | – | – |
| Goals (personal) | 4 | .89 | – | – |
| Goals (eating) | – | – | 6 | .84 |
| Goals (drinking) | – | – | 4 | .71 |
| Reinforcement | 2 | .80 | – | – |
| Reinforcement (control) | – | – | – | .82 |
| Reinforcement (mind) | – | – | – | .91 |
| Affect (positive) | 5 | .91 | 2 | .76 |
| Affect (negative) | 5 | .88 | 4 | .83 |
Note. Abbreviations: PBC perceived behavioural control