ICC and sample size estimates for primary outcomes
| Outcome | ICC | Design effect (30–40 patients per practice) | Effect size or difference in proportions | Sample size per group |
| Mean Health Literacy Score | 0.014 | 1.43 | 0.4 | 140 |
| Mean Diet score | 0.001 | 1.03 | 0.21 | 367 |
| Mean Physical Activity score | 0.018 | 1.56 | 0.28 | 312 |
| Mean BMI | 0.042 | 2.30 | 0.30 | 401 |
| Mean systolic BP | 0.057 | 2.77 | 0.39 | 285 |
BMI, body mass index; BP, blood pressure; ICC, intracluster correlation coefficient.