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Scientometrics

, Volume 69, Issue 1, pp 57–67 | Cite as

A semi-parametric modeling of firms' R&D expenditures with zero values

  • Seung-Hoon Yoo
  • Hye-Seon Moon
Article

Summary

Modeling firms' R&D expenditures often become complicated due to the zero values reported by a significant number of firms. The maximum likelihood (ML) estimation of the Tobit model, which is usually adopted in this case, however, is not robust to heteroscedastic and/or non-normal error structure. Thus, this paper attempts to apply symmetrically trimmed least squares estimation as a semi-parametric estimation of the Tobit model in order to model firms' R&D expenditures with zero values. The result of specification test indicates the semi-parametric estimation outperforms the parametric ML estimation significantly.

Keywords

Tobit Model Lagrangian Multiplier Test Investment Ratio Expenditure Equation Sales Amount 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag/Akadémiai Kiadó 2006

Authors and Affiliations

  • Seung-Hoon Yoo
    • 1
  • Hye-Seon Moon
    • 2
  1. 1.School of Business and Economics, Hoseo University
  2. 2.Korea Institute of Science and Technology Evaluation and Planning

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