New research investigates the effect of preventive health using field experiments.
Results have important policy conclusions:
1. poor households do not take preventative health measures because they are unwilling to pay for them.
2. information campaigns have relatively low impact
3. peer effects matter, however, only when information asymmetry is likely to matter
There is more: Jennifer M. Meredith, Jonathan Robinson, Sarah Walker, Bruce Wydick, "Keeping the Doctor Away: Experimental Evidence on Investment in Preventative Health Products", NBER Working Paper No. 19312.