Table 6 Combined parameter estimations of the gravity model of migration
|  | 2004–2007 (∆t = 4) | 2008–2011 (∆t = 4) | 2012–2015 (∆t = 4) | 2004–2015 (∆t = 16) | ||||
|---|---|---|---|---|---|---|---|---|
Average | Variance | Average | Variance | Average | Variance | Average | Variance | |
δ | − 1.94 | 2.9 × 10−2 | − 2.37 | 4 × 10−2 | − 2.28 | 4.7 × 10−2 | − 2.19 | 6.8 × 10−2 |
γ (distance) | 0.69 | 1 × 10−2 | 0.80 | 1.1 × 10−4 | 0.78 | 3 × 10−5 | 0.76 | 5.4 × 10−3 |
MSE | 1.62 | 2 × 10−1 | 2.41 | 2 × 10−3 | 2.38 | 2 × 10−3 | 2.14 | 2 × 10−1 |
Population | ||||||||
 α (source) | 0.47 | 4.1 × 10−3 | 0.54 | 3.3 × 10−4 | 0.57 | 2.7 × 10−4 | 0.53 | 3.2 × 10−3 |
 β (destination) | 0.45 | 5.6 × 10−3 | 0.56 | 1.2 × 10−4 | 0.57 | 1.2 × 10−4 | 0.53 | 4.5 × 10−3 |
Political affiliation | ||||||||
 α (source) | 0.22 | 2 × 10−4 | 0.01 | 6.3 × 10−4 | 0.14 | 1.2 × 10−3 | 0.12 | 8.4 × 10−3 |
 β (destination) | 0.64 | 9.5 × 10−3 | 0.42 | 3.9 × 10−3 | 0.61 | 8.7 × 10−4 | 0.56 | 1.5 × 10−2 |
Poverty | ||||||||
 α (source) | 0.27 | 1.5 × 10−2 | 0.57 | 8.4 × 10−3 | 0.42 | 1.9 × 10−3 | 0.42 | 2.3 × 10−2 |
 β (destination) | 0.34 | 1.8 × 10−2 | 0.57 | 1.2 × 10−2 | 0.43 | 4.2 × 10−3 | 0.45 | 1.9 × 10−2 |
Unemployment | ||||||||
 α (source) | 0.73 | 1.8 × 10−3 | 0.60 | 1.7 × 10−2 | 0.64 | 4 × 10−3 | 0.66 | 9.4 × 10−3 |
 β (destination) | 0.71 | 7.8 × 10−3 | 0.58 | 2 × 10−2 | 0.62 | 7 × 10−3 | 0.64 | 1.2 × 10−2 |