Influenza Vaccination Campaigns: Is an Ounce of Prevention Worth a Pound of Cure?
利用三重差分法评估了安大略省扩大流感疫苗接种覆盖面的总体影响和外部性效应，发现扩大接种带来健康改善，且对老年人有显著的外部收益。
This paper estimates the overall impact and externality effects of an influenza vaccination program expanding coverage outside the typical target group. Using a triple-difference design, which exploits the introduction of a broad based vaccination program in Ontario and the quality of the vaccine from year to year, I link higher vaccination to health improvements. Results indicate coverage expansion leads to large excess gains for program-regions; benefits exhibit decreasing returns corresponding to a standard model of disease dynamics; and substantial external benefits accrue to older adults.