This study compares how well three semi-nonparametric functions, the Fourie
r flexible form, asymptotically ideal model, and neural networks, approxima
te simulated production data. Results show that higher order series expansi
ons better approximate the true technology for data sets that have little o
r no measurement error. For highly nonlinear technologies and much measurem
ent error, lower order expansions may be appropriate. (C) 2000 Elsevier Sci
ence S.A. All rights reserved. JEL classification: C14; D12.