Table 5.
Number of apps receiving usability severity scores for each persuasive health technology heuristic.
| Heuristic | No issues (score=0) | Cosmetic issues (score=1) | Minor issues (score=2) | Major issues (score=3) | Usability catastrophe (score=4) |
| Appropriate functionality | 0 | 0 | 5 | 26 | 2 |
| Not irritating or embarrassing | 0 | 1 | 9 | 20 | 3 |
| Protects user privacy | 2 | 0 | 4 | 5 | 22 |
| Use of positive motivation strategies | 0 | 3 | 1 | 17 | 12 |
| Usable and aesthetically appealing design | 0 | 6 | 13 | 12 | 2 |
| Accuracy of user information | 0 | 0 | 3 | 14 | 16 |
| Appropriate time and place | 0 | 4 | 2 | 25 | 2 |
| Visibility of user status | 0 | 4 | 1 | 20 | 8 |
| Customizability | 0 | 0 | 5 | 10 | 18 |
| Educates users | 0 | 0 | 4 | 20 | 9 |