ACO entry and SNF financial outcomes: causal models

Effects of SNF entry into MSSP ACOs (single entry, no exit) on per-patient-day operating expenses, net and gross patient revenue, net income from patient services, and total other income. Treated facilities are matched to 4 controls in the same county (state fallback).

Generated 2026-10-28 10:40. Cost report rules: 360-370 day reports; FY-to-CY attribution OFF; gov't/territory exclusion ON; other income NA-to-zero ON; G-3 winsorized by year ON.

Table 1. Matched sample: treated facilities and controls by event type
event n_matched_pairs n_treated n_unique_controls pairs_county pairs_state
Entries 984 246 857 780 204
4 controls per treated, same county with state fallback (H0c).
Table 2. Operating expenses per patient day: TWFE vs. CS vs. SA vs. Stacked DID
Model Event ATT SE
TWFE Entries −2.068 13.56
Callaway-Sant'Anna Entries −21.68 35.14
Sun-Abraham Entries −51.21 40.08
Stacked DID Entries −22.19 10.52
Table 3. Stacked DID ATTs, all five outcomes
Outcome Event ATT SE
Total operating expenses per patient day Entries −22.19 10.52
Net patient revenue per patient day Entries −8.362 10.91
Gross patient revenue per patient day Entries −23.91 12.75
Net income from patient services per patient day Entries 12.35 9.315
Total other income Entries 418,400 266,600
Matched sample, facility-clustered SEs.
Table 4. Event-study coefficients, all outcomes
Outcome ATT SE ci_lo ci_hi p_value p_fmt n_post_periods
Total operating expenses per patient day −22.19 10.52 −42.80 −1.568 0.03494 0.035 3
Net patient revenue per patient day −8.362 10.91 −29.74 13.01 0.4432 0.443 3
Gross patient revenue per patient day −23.91 12.75 −48.90 1.066 0.06060 0.061 3
Net income from patient services per patient day 12.35 9.315 −5.910 30.61 0.1850 0.185 3
Total other income 418,400 266,600 −104,100 940,900 0.1165 0.117 3
Table 5. Joint Wald pre-trend tests, Stacked DID
Outcome Event n_pre_coefs F_stat df1 df2 p_value pretrend_flag
Total operating expenses per patient day Entries 4 1.189 4 2,093 0.3135 Pass -- no evidence against parallel pre-trends
Net patient revenue per patient day Entries 4 0.4237 4 2,092 0.7916 Pass -- no evidence against parallel pre-trends
Gross patient revenue per patient day Entries 4 0.6815 4 2,092 0.6048 Pass -- no evidence against parallel pre-trends
Net income from patient services per patient day Entries 4 1.169 4 2,093 0.3223 Pass -- no evidence against parallel pre-trends
Total other income Entries 4 1.223 4 2,092 0.2989 Pass -- no evidence against parallel pre-trends
p < .05 flags doubtful parallel pre-trends.
Table 6. Honest DiD breakdown values (relative magnitudes)
Outcome Event breakdown_Mbar note
Total operating expenses per patient day Entries 0 ok
Net patient revenue per patient day Entries 0 ok
Gross patient revenue per patient day Entries 0 ok
Net income from patient services per patient day Entries 0.5000 ok
Total other income Entries 0 ok
Rambachan & Roth (2023).
Table 7. Per-day outcome winsorization cutoffs (pooled 1/99, robustness)
outcome p01 p99
opex_per_day 199.5 2,121
patient_rev_net_per_day 190.9 1,621
patient_rev_gross_per_day 206.4 1,848
patient_netinc_per_day −848.7 96.96
total_other_income −37,590 17,920,000
Table 8. Raw vs. winsorized ATTs (robustness)
Outcome Event Version ATT SE
Total operating expenses per patient day Entries Raw −22.19 10.52
Total operating expenses per patient day Entries Winsorized 4.563 7.863
Net patient revenue per patient day Entries Raw −8.362 10.91
Net patient revenue per patient day Entries Winsorized 12.18 5.557
Gross patient revenue per patient day Entries Raw −23.91 12.75
Gross patient revenue per patient day Entries Winsorized 2.608 7.084
Net income from patient services per patient day Entries Raw 12.35 9.315
Net income from patient services per patient day Entries Winsorized −1.310 5.124
Total other income Entries Raw 418,400 266,600
Total other income Entries Winsorized 24,150 112,500
Table 9. Pre-trend tests on winsorized outcomes (robustness)
Outcome Event n_pre_coefs F_stat df1 df2 p_value pretrend_flag
Total operating expenses per patient day Entries 4 2.205 4 3,840 0.06599 Pass -- no evidence against parallel pre-trends
Net patient revenue per patient day Entries 4 1.418 4 3,839 0.2254 Pass -- no evidence against parallel pre-trends
Gross patient revenue per patient day Entries 4 1.436 4 3,839 0.2195 Pass -- no evidence against parallel pre-trends
Net income from patient services per patient day Entries 4 0.4306 4 3,840 0.7866 Pass -- no evidence against parallel pre-trends
Total other income Entries 4 1.689 4 3,731 0.1497 Pass -- no evidence against parallel pre-trends
Table 10. Honest DiD on winsorized outcomes (robustness)
Outcome Event breakdown_Mbar note
Total operating expenses per patient day Entries 0 ok
Total operating expenses per patient day Exits 0 ok
Net patient revenue per patient day Entries 0 ok
Net patient revenue per patient day Exits 0 ok
Gross patient revenue per patient day Entries 0 ok
Gross patient revenue per patient day Exits 0 ok
Net income from patient services per patient day Entries 0 ok
Net income from patient services per patient day Exits 0 ok
Total other income Entries 0 ok
Total other income Exits 0 ok
Unadjusted trend entries grossday calendar
Figure 1. Unadjusted trend entries grossday calendar
Unadjusted trend entries grossday event
Figure 2. Unadjusted trend entries grossday event
Unadjusted trend entries netinc calendar
Figure 3. Unadjusted trend entries netinc calendar
Unadjusted trend entries netinc event
Figure 4. Unadjusted trend entries netinc event
Unadjusted trend entries opex calendar
Figure 5. Unadjusted trend entries opex calendar
Unadjusted trend entries opex event
Figure 6. Unadjusted trend entries opex event
Unadjusted trend entries otherinc calendar
Figure 7. Unadjusted trend entries otherinc calendar
Unadjusted trend entries otherinc event
Figure 8. Unadjusted trend entries otherinc event
Unadjusted trend entries revday calendar
Figure 9. Unadjusted trend entries revday calendar
Unadjusted trend entries revday event
Figure 10. Unadjusted trend entries revday event
Unadjusted trend entries rn calendar
Figure 11. Unadjusted trend entries rn calendar
Unadjusted trend entries rn event
Figure 12. Unadjusted trend entries rn event
Unadjusted trends entries combined all outcomes
Figure 13. Unadjusted trends entries combined all outcomes
Event study entries operating expenses
Figure 14. Event study entries operating expenses
Event study entries operating expenses per day
Figure 15. Event study entries operating expenses per day
Stacked did entries all outcomes
Figure 16. Stacked did entries all outcomes
Stacked did entries combined all outcomes
Figure 17. Stacked did entries combined all outcomes
Honest did entries grossday
Figure 18. Honest did entries grossday
Honest did entries netinc
Figure 19. Honest did entries netinc
Honest did entries opex
Figure 20. Honest did entries opex
Honest did entries otherinc
Figure 21. Honest did entries otherinc
Honest did entries revday
Figure 22. Honest did entries revday
Honest did entries grossday winsorized
Figure 23. Honest did entries grossday winsorized
Honest did entries netinc winsorized
Figure 24. Honest did entries netinc winsorized
Honest did entries opex winsorized
Figure 25. Honest did entries opex winsorized
Honest did entries otherinc winsorized
Figure 26. Honest did entries otherinc winsorized
Honest did entries revday winsorized
Figure 27. Honest did entries revday winsorized
Stacked did entries all outcomes winsorized
Figure 28. Stacked did entries all outcomes winsorized
Stacked did entries grossday winsorized
Figure 29. Stacked did entries grossday winsorized
Stacked did entries netinc winsorized
Figure 30. Stacked did entries netinc winsorized
Stacked did entries opex winsorized
Figure 31. Stacked did entries opex winsorized
Stacked did entries otherinc winsorized
Figure 32. Stacked did entries otherinc winsorized
Stacked did entries revday winsorized
Figure 33. Stacked did entries revday winsorized
Unadjusted trend entries grossday calendar winsorized
Figure 34. Unadjusted trend entries grossday calendar winsorized
Unadjusted trend entries grossday event winsorized
Figure 35. Unadjusted trend entries grossday event winsorized
Unadjusted trend entries netinc calendar winsorized
Figure 36. Unadjusted trend entries netinc calendar winsorized
Unadjusted trend entries netinc event winsorized
Figure 37. Unadjusted trend entries netinc event winsorized
Unadjusted trend entries opex calendar winsorized
Figure 38. Unadjusted trend entries opex calendar winsorized
Unadjusted trend entries opex event winsorized
Figure 39. Unadjusted trend entries opex event winsorized
Unadjusted trend entries otherinc calendar winsorized
Figure 40. Unadjusted trend entries otherinc calendar winsorized
Unadjusted trend entries otherinc event winsorized
Figure 41. Unadjusted trend entries otherinc event winsorized
Unadjusted trend entries revday calendar winsorized
Figure 42. Unadjusted trend entries revday calendar winsorized
Unadjusted trend entries revday event winsorized
Figure 43. Unadjusted trend entries revday event winsorized