| Methods |
Data are for Wyoming. See McMahon 1995b |
| Participants |
See McMahon 1995b |
| Interventions |
See McMahon 1995b |
| Outcomes |
See McMahon 1995b |
| Notes |
— |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
"The two states were divided into 40 geographic regions defined by zip code aggregates (24 in Montana, 16 in Wyoming); in each state four regions were randomly selected as intervention sites." |
| Allocation concealment (selection bias) |
Unclear risk |
No statement |
| Blinding (performance bias and detection bias)
All outcomes |
Unclear risk |
No statement |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Influenza vaccination data are collected by Medicare as billing claims; 96% of those ≥ 65 years are covered by Medicare Part B, which processes all billing claims for influenza vaccination. |
| Selective reporting (reporting bias) |
Low risk |
No selective reporting |
