Table 1.
Mutual Shannon information entropy, Autoregressive Integrated Moving Average or Autoregressive Integrated Moving Average with External Variable model parameters, and Akaike Information Criteria values in different quarters of 2016.
| Quarters | Original + Case | Retweeting without commenting + Case | Reply + Case | |
| Q1 | ||||
|
|
Mutual Info | 0.04 | 0.01 | 0.09 |
| ARIMA(X)a Par | 2, 0, 3 | 2, 1, 3 | 2, 0, 2 | |
| dAICb | –2.25c (976.61, 974.36) |
–1.88c (1341.51, 1339.63) |
–1.21c (950.05, 948.84) |
|
| Q2 | ||||
|
|
Mutual Info | 0.13 | 0.17 | 0.29 |
| ARIMA(X) Par | 2, 1, 3 | 2, 1, 3 | 0, 1, 1 | |
| dAIC | 0.96 (722.54, 723.50) |
–0.88c (1207.14, 1206.26) |
1.88 (709.18, 711.06) |
|
| Q3 | ||||
|
|
Mutual Info | 0.02 | 0.08 | 0.02 |
| ARIMA(X) Par | 1, 1, 1 | 2, 1, 2 | 2, 1, 2 | |
| dAIC | 1.95 (719.51, 721.46) |
1.82 (1172.01, 1173,83) |
–0.62c (738.76, 738.14) |
|
| Q4 | ||||
|
|
Mutual Info | 0.01 | 0.07 | 0.01 |
| ARIMA(X) Par | 2, 0, 3 | 0, 1, 2 | 0, 0, 1 | |
| dAIC | –0.59c (453.28, 452.69) |
1.62 (917.84, 919.46) |
1.97 (353.23, 355.20) |
|
aARIMA(X): Autoregressive Integrated Moving Average (with External Variable).
bdAIC: difference in Akaike information criterion.
cNegative dAIC value indicates better performance of the ARIMAX model compared with its corresponding ARIMA model; hence, including Zika case counts improves the model performance.