| Model | K | AIC | ΔAIC | AICwt |
| p(month + effort + year) | 9 | 3817.75 | 0.00 | 1.00 |
| p(month + effort) | 6 | 3845.08 | 27.33 | 0.00 |
| p(effort + year) | 8 | 3877.02 | 59.27 | 0.00 |
| p(month + year) | 8 | 3899.98 | 82.22 | 0.00 |
| p(effort) | 5 | 3903.50 | 85.75 | 0.00 |
| p(month) | 5 | 3931.68 | 113.93 | 0.00 |
| p(year) | 7 | 3950.48 | 132.72 | 0.00 |
| p(.) | 4 | 3980.98 | 163.23 | 0.00 |