Applying an outlier robust extension of the data envelopment analysis (DEA) followed by a geoadditive regression analysis, this study identifies and decomposes the efficiency of 439 German regions in using infrastructure and human capital. The findings show that the regions' efficiency is driven...

Simar and Wilson (J. Econometrics, 2007) provided a statistical model that can rationalize two-stage estimation of technical efficiency in nonparametric settings. Two-stage estimation has been widely used, but requires a strong assumption: the second-stage environmental variables cannot affect...