Table 2 Example structure of the serial outcome variables used in the logistic regression and the accelerated failure time (AFT) models as derived from the 48 week ZIKV surveillance data for a positive outcome (y = 1), negative outcome (y = 0), or right-censored data
Modelling approach | Possible outcome, y | Weeks of study period | |||||||
|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | … | 48 | ||
Logistic regression | Index case | 1 | 1 | 1 | 1 | 1 | 1 | … | 1 |
First case detected in week 3 | 0 | 0 | 1 | 1 | 1 | 1 | … | 1 | |
No cases detected | 0 | 0 | 0 | 0 | 0 | 0 | … | 0 | |
AFT model | Index case | 1 | – | – | – | – | – | … | – |
First case detected in week 3 | 0 | 0 | 1 | – | – | – | … | – | |
No cases detected | 0 | 0 | 0 | 0 | 0 | 0 | … | 0 | |