References Aigner, D.J., Lovell, C.A.K. and Schmidt, P. (1977), Formulation and estimation of stochastic frontier models, Journal of Econometrics, 6, 21-37. Bonanno, G., De Giovanni, D., Domma, F. (2017), The ‘wrong skewness’ problem: a re-specification of stochastic frontiers, Journal of Productivity Analysis, 47(1), 49-64. Chen, Y.T. and Wang, H.J. (2012), Centered-residuals-based moment tests for stochastic frontier models, Econometric Reviews, 31, 625-653. Coelli, T.J. (1995), Estimators and hypothesis tests for a stochastic frontier function: a Monte Carlo analysis, Journal of Productivity Analysis, 6, 247-268. Coelli, T.J., Prasada Rao, D.S., O Donnell, C.J. and Battese, G.E. (2005). An Introduction to Efficiency and Productivity Analysis. 2nd Edition, Springer, New York. Fan, Y. and Li, Q. (1996), Consistent model specification tests: Omitted variables and semiparametric functional forms, Econometrica, 64, 865-890. Fan, Y., Li, Q. and Weersink, A. (1996), Semiparametric estimation of stochastic production frontier, Journal of Business and Economics Statistics, 14, 460-468. Fried, H., Lovell, C.A.K. and Schmidt, S. (2008), The Measurement of Productive Efficiency and Productivity Change, Oxford University Press, New York. González-Manteiga, W. and Crujeiras, R.M. (2013), An updated review of Goodness-of-Fit tests for regression models, Test, 22, 361-411. Greene, W.H. (1990), A Gamma-Distributed Stochastic Frontier Model, Journal of Econometrics, 46, 141-163. Greene, W.H. (2005), Reconsidering heterogeneity in panel data estimators of the stochastic frontier model Journal of Econometrics, 126(2), 269-303. Kopp, R.J., and Mullahy, J. (1990), Moment-based estimation and testing of stochastic frontier models, Journal of Econometrics, 46, 165-183. Kumbhakar, S. and Lovell, C.A.K. (2000), Stochastic Frontier Analysis, Cambridge University Press, Cambridge. Kumbhakar, S.C., Park, B.U., Simar, L. and Tsionas, E.G. (2007), Nonparametric stochastic frontiers: A local likelihood approach, Journal of Econometrics, 137(1), 1-27. Lee, L.F. (1983), A test for distributional assumptions for the stochastic frontier functions, Journal of Econometrics, 22, 245-267. Meeusen, W., and Broeck, J.v.D. (1977), Efficiency estimation from Cobb-Douglas production functions with composed error, International Economic Review, 18(2), 435-444. Schmidt, P., and Lin, T.F. (1984), Simple tests of alternative specifications in stochastic frontier models, Journal of Econometrics, 24, 349-361. Simar, L., Van Keilegom, I. and Zelenyuk, V. (2016), Nonparametric least squares methods for stochastic frontier models. Journal of Productivity Analysis, in press. Simar, L. and Wilson, P. (2015), Statistical approaches for nonparametric frontier models: A guided tour, International Statistical Review, 83, 77-110. Stute, W. (1997), Nonparametric model checks for regression, Annals of Statistics, 25, 613-641. Stute, W., Gonz´ales-Manteiga, W. and Presedo-Quindimil, M. (1998), Bootstrap approximation in model checks for regression, Journal of the American Statistical Association, 93, 141-149. Tsekouras, K., Chatzistamoulou, N., Kounetas, K. (2017), Productive performance, technology heterogeneity and hierarchies: Who to compare with whom, International Journal of Production Economics , 193, 465-478. Wang, W.S., Amsler, C. and Schmidt, P. (2011), Goodness of fit tests in stochastic frontier models, Journal of Productivity Analysis, 35, 95-118. Zheng, J.X. (1996), A consistent test of functional form via nonparametric estimation techniques, Journal of Econometrics, 75, 263-289.