I am working on a study with binary outcomes by using difference-in-difference. Traditionally, we know that outcomes usually are continuous in DID model. However, there is a paper discussed using categorical outcomes in DID analysis. Therefore, I am wondering if it is able to procedure in SAS.
(Graves JA, Fry C, McWilliams JM, Hatfield LA. Difference-in-differences for categorical outcomes. Health Serv Res. 2022 Jun;57(3):681-692.)
Also, as my understanding, they used transition effect in DID model. I am unsure is it estimate the difference of probabilities among two groups. Below is the example interpretation, I appreciate more interpretation and knowledge provided.
Example Interpretation:
Transition Control Group (R0R_0R0) Treatment Group (R1R_1R1) Difference (RDD)
| Stayed No (P_{00}) | 70% | 60% | -10pp |
| No → Yes (P_{01}) | 20% | 35% | +15pp |
| Yes → No (P_{10}) | 5% | 3% | -2pp |
| Stayed Yes (P_{11}) | 5% | 7% | +2pp |
- A 15pp increase in P01P_{01}P01 means the intervention led to more patients transitioning to intervention.
