Variables | Level | First differences | ||
---|---|---|---|---|
Intercept | Intercept and trend | Intercept | Intercept and trend | |
SPI |  − 1.611 |  − 2.347 |  − 16.837* |  − 16.857* |
IPI |  − 1.689 |  − 1.818 |  − 4.875* |  − 5.060* |
SPI− |  − 0.398 |  − 1.240 |  − 17.096* |  − 17.170* |
IPI− | 0.208 |  − 0.713 |  − 6.730* |  − 7.869* |
SPI+ |  − 0.979 |  − 0.987 |  − 16.167* |  − 16.451* |
IPI+ | 0.055 |  − 0.889 |  − 5.925* |  − 7.111* |