# Table 6: Robustness of impact estimates to alternative classifications and specification

_Panel A: Models with alternative payment methods classifications_

|Dependent variable|Preferred<br>model|FFS|Impact|PBP|Impact|
|---|---|---|---|---|---|
|Inpatient admissions|DID|0.42**|2.6%|0.00|0.0%|
|Hosp discharges - circulatory|DID|163.84**|8.4%|112.09|5.8%|
|Hosp discharges - cerebrovas|DID|23.07**|6.6%|-1.99|-0.6%|
|Hosp discharges - respiratory|RT|146.76**|7.1%|50.07|2.4%|
|Hosp discharges - digestive|DID|105.07**|6.4%|7.15|0.4%|
|Hosp discharges - musculo|DID|42.21|5.3%|-8.11|-1.0%|
|Length of stay|DT|-0.06|-0.5%|-0.26|-2.0%|
|Hospital beds|DID|-0.03|-0.4%|-0.34|-4.2%|
|Bed occupancyrate|DT|-0.22|-0.3%|-3.33**|-4.6%|
|Health expenditures - Total|DID|75.45**|18.4%|43.30*|10.6%|
|Health expenditures - Public|DID|50.60**|16.7%|23.17|7.6%|
|Health expenditures - Private|DID|24.85**|23.5%|20.13|19.1%|
|SDR ischemic heart disease|DID|-4.47|-1.4%|-4.56|-1.5%|
|SDR diabetes|RT|-0.72|-4.9%|-0.91|-6.1%|
|SDR cerebrovascular diseases|DID|-2.40|-1.4%|-6.87|-3.9%|
|SDR female breast cancer|DID|0.52|2.4%|-0.16|-0.7%|
|SDR appendicitis|DID|-0.01|-2.3%|0.02|5.7%|
|SDR hernia & intestinal|DID|-0.04|-1.8%|0.03|1.6%|
|SDR adverse effects|DID|0.04|20.6%|0.02|7.3%|

_Panel B: Models with lagged payment methods dummies added_

|Dependent variable|Preferred<br>model|FFS|Lagged<br>FFS|PBP|Lagged<br>PBP|Lin<br>combinat<br>FFS var<br>Coef|ear<br>ion: two<br>iables<br>Impact|Lin<br>combinat<br>PBP va<br> <br>Coef|ear<br>ion: two<br>riables<br>Impact|
|---|---|---|---|---|---|---|---|---|---|
|Inpatient admissions|DID|0.48**|0.73**|0.00|0.50|1.21**|7.5%|0.50|3.1%|
|Hosp discharges - circulatory|DID|153.62**|89.49|65.65|0.68|243.11**|12.5%|<br>66.33|3.4%|
|Hosp discharges - cerebrovas|DID|19.20|6.82|-12.66|14.31|26.02|7.4%|1.65|0.5%|
|Hosp discharges - respiratory|DID|160.39**|169.83**|64.39|164.99*|330.22**|16.3%|229.38**|11.3%|
|Hosp discharges - digestive|RT|102.68**|110.68**|17.37|56.01*|213.36**|13.1%|<br>73.38|4.5%|
|Hosp discharges - musculo|DID|47.76*|63.64**|-24.92|25.53|111.40**|14.1%|<br>0.62|0.1%|
|Length of stay|DID|-0.32|-0.06|-0.42**|-0.14|-0.38|-3.1%|-0.56**|-4.5%|
|Hospital beds|DID|0.05|0.01|-0.04|0.13|0.05|0.7%|0.09|1.1%|
|Bed occupancyrate|DID|2.02|3.68**|-2.79|2.51*|5.70**|7.9%|-0.28|-0.4%|
|Health expenditures - Total|DID|73.00**|2.17|55.69**|32.06**|75.17*|18.4%|87.75**|21.4%|
|Health expenditures - Public|DID|49.58*|6.22|36.03|31.00**|55.80*|18.4%|67.03**|22.1%|
|Health expenditures - Private|DID|23.42*|-4.04|19.66*|1.06|19.37|18.2%|<br>20.72|19.5%|
|SDR ischemic heart disease|DID|-4.61|0.56|-12.75**|-4.89|-4.05|-1.3%|-17.64**|-5.7%|
|SDR diabetes|DID|-0.83|-1.26|-1.26|-0.39|-2.09*|-13.9%|-1.65*|-11.0%|
|SDR cerebrovascular diseases|DID|-2.39|-0.39|-8.30**|3.62|-2.78|-1.6%|-4.68|-2.6%|
|SDR female breast cancer|DID|0.39|0.00|-0.54|0.16|0.39|1.8%|-0.38|-1.7%|
|SDR appendicitis|DID|0.00|-0.03|-0.03|-0.07*|<br>-0.03|-10.2%|<br>-0.10|-34.2%|
|SDR hernia & intestinal|RT|0.02|0.06|0.01|-0.07|0.09|3.9%|-0.06|-2.8%|
|SDR adverse effects|DID|-0.01|-0.06|-0.15|-0.03|-0.07|-32.6%|<br>-0.17|-79.4%|

_Notes:_ Results in each panel refer to the coefficients of the fee-for-service (FFS) and patient-based (PBP) payment methods dummies estimated in the preferred model for each outcome—difference-in-differences (DID), random trend (RT) or differential trend (DT) model, implied by the corresponding tests of the parallel trend assumption (not shown). In Panel B, the coefficients of the first lags of the payment methods dummies and the linear combinations of FFS (level and lag) and PBP (level and lag) are also reported. The symbols * and ** denote statistical significance at the 10% and 5% levels, respectively, according to p-values from two-sided _t_ -tests with clusterrobust standard errors (not shown). FFS and PBP percentage impacts implied by the corresponding coefficients are calculated over the mean outcome variable in the corresponding estimating sub-sample.