Appendix A.
Poisson regressions of narrowness of prescribing on characteristics of doctors and patients
| (1) Statin | (2) PPI | (3) SS/NRI | (4) Antihistamines | (5) Calcium Channel Blockers | |
|---|---|---|---|---|---|
| Y = Number of drugs prescribed as initial prescriptions | |||||
| Combinations of chronic conditions | 0.144*** (0.0197) | 0.179*** (0.0543) | 0.274*** (0.0383) | 0.0317 (0.0471) | 0.172* (0.0705) |
| Combinations of chronic conditions | −0.00691*** (0.00134) | −0.0191* (0.00799) | −0.0225*** (0.00340) | 0.00174 (0.00679) | −0.0114 (0.00596) |
| Different copay orderings | −0.0106 (0.0170) | 0.0442* (0.0172) | 0.0776*** (0.0217) | 0.123*** (0.0171) | 0.0901* (0.0399) |
| Number of plans | 0.108*** (0.0177) | 0.0707*** (0.0168) | 0.0814** (0.0295) | 0.00421 (0.0138) | 0.118 (0.0768) |
| Number of plans (squared) | −0.00670*** (0.00136) | −0.00315** (0.00109) | −0.00808** (0.00252) | 0.0000271 (0.000762) | −0.0198* (0.00907) |
| Initial prescriptions observed | 0.122*** (0.00969) | 0.119*** (0.0148) | 0.265*** (0.0216) | 0.0231** (0.00716) | 0.427*** (0.0405) |
| Initial prescriptions (squared) | −0.00167*** (0.000221) | −0.00168*** (0.000411) | −0.00226*** (0.000476) | −0.000399** (0.000140) | −0.0105*** (0.00148) |
| Patients with prior use in class | 0.0936*** (0.0138) | 0.0917*** (0.0177) | 0.131*** (0.0216) | 0.0822*** (0.0128) | 0.0134 (0.0431) |
| Patients with prior use (squared) | −0.00166 (0.00145) | −0.00701** (0.00234) | −0.00914** (0.00281) | −0.00216 (0.00117) | 0.00681 (0.00674) |
| Half years with a prescription | 0.159*** (0.0152) | 0.0793*** (0.0166) | 0.155*** (0.0244) | 0.137*** (0.0148) | 0.102** (0.0346) |
| Observations | 8923 | 6621 | 5866 | 4788 | 1975 |
| ll | −15357.9 | −10940.8 | −10619.1 | −7370.9 | −3474.9 |
| ll_0 | −15906.1 | −11174.1 | −11293.6 | −7465.4 | −3589.9 |