From: Effective methods for reactivating inactive blood donors: a stratified randomised controlled study
 | Cost per participant (C) (RMB¥) | Effectiveness (E) (%) | ΔC | ΔE | Ratio (ΔC/ΔE) |
---|---|---|---|---|---|
Control group | – | 7.4 | – | – | – |
Telephone group | 3.9 | 8.1 | 3.9 | 0.007 | 557.1 |
SMS group | 0.7 | 8.4 | 0.7 | 0.010 | 70 |