Table 2

Instrumental-variables models of countries’ research impact and innovation

Model (1): Research impactModel (2): Innovation
Contribution of international collaborators68.272 (158.432)8.109 (11.384)
No of articles per organisation33.668 (48.883)−2.363 (4.174)
Efficiency211.320 (63.625)18.819 (6.108)
Geographical entropy244.527 (55.760)30.850 (4.641)
Constant74.600 (106.865)7.116 (10.900)
No observations5656
Centred R2 (uncentred R2)0.572 (0.614)0.519 (0.587)
Root MSE (Embedded Image)184.417.63
  • The models are efficient GMM instrumental-variables estimators with SEs robust to heteroskedasticity. Robust SEs of parameter estimates are within parentheses. Reported values of the square root of the MSE refer to the estimated standard deviation Embedded Image of the idiosyncratic disturbance. Estimated parameters in boldface are statistically significant at the 1% level (p<0.01).

  • GMM, generalised methods-of-moments; MSE, mean squared error.