Dossier de candidature pour l’obtention de l’Habilitation Universitaire

Tawfik Ben Amor and Mohamed Goaied (2010) "Stochastic Varying Coefficient Frontier Model in the Estimation of Technical Efficiency and Technical Efficiency of Specific Input", Agricultural Journal Vol 5-6 2 p 329-337

Abstract: In this study, we propose a hybrid of a stochastic frontier regression. The proposed model and estimation differ from the conventional model of Aigner, Lovell, and Schmidt. The model combines a stochastic frontier regression and a random coefficient regression:(a Stochastic Varying Coefficient Frontier Model) (SVCF) to estimate the Technical Efficiency (TE) and Single Factor Specific Technical Efficiency (SFTE) of Tunisian farmers for irrigated crops such as vegetable farming cereal and fruit-trees. The proposed single-factor measure of efficiency is based on Kopp's notion of non-radial technical efficiency and it is shown that in the context of the SVCF model could provide firm-specific estimates even with inflexible production frontiers, such as the Cobb-Douglas. The empirical results indicate that the mean value of technical efficiency for all farms is estimated to be 54.7% for vegetable farming, 67.2% for cereal, and 71.2 …

Tawfik Ben Amor and Christophe Muller (2010) Application of stochastic production frontier in the estimation of technical efficiency of irrigated agriculture in Tunisia. Agricultural Journal 2010 Vol.5 No.2 pp.50-56

Abstract: In this study, we estimate agricultural technology for Tunisian peasants, accounting for the crop choice of peasants and distinguishing inputs for individual crops such as vegetable farming cereal and fruit trees. The study employed the use of cross-section data from a distinguishable irrigated crops survey conducted on a sample of 218 farmers from 11 regions in Tunisia. The data were collected with the aid of a structured questionnaire and were later analyzed. The Cobb Douglass production frontier model is employed to analyse the data collected. Among the irrigated crop farmers, the significant variables were: farmuar manual fertiliser quantity, labor, mechanic traction and among of irrigated water applied. The estimated sigma square (σ2) and gamma (γ) are widely significant for all irrigated crops and revealed that >85% of the variation in the Tunisian irrigated output among farmers in the study area is due to the differences in their efficiencies. However, we find that predicted technical efficiency widely varies across farms and crops from an average of 54.7% for vegetable farming up to 80.6% for fruit trees. The study also revealed the existing inefficiency effects among the farmers as education, farmer's age, irrigation techniques, lack of education, and property of land.

Tawfik Ben Amor and Thuraya Mellah (2016) Performance of the Tunisian Water Utility: An input-distance function approach. Utilities Policy Volume 38, February 2016, Pages 18-32 https://doi.org/10.1016/j.jup.2015.11.001.

Abstract: The main objective of this paper is to analyze the performance pattern in the Tunisian drinking water industry. The industry is a state monopoly, administered by the Tunisian Water Utility (TWU) since 1968. We apply the stochastic distance frontier method to TWU data over a period of 11 years, from 1999 to 2009. This approach is used to estimate water production technology, measure technical efficiency levels and total factor productivity growth, and investigate the factors influencing efficiency levels and those driving productivity growth. The results suggest that performance-based regulation can improve efficiency and enhance productivity in the Tunisian water industry

Tawfik Ben Amor (2022) Heteroskedastic Stochastic Cost Frontier Approach in the Estimation of Cost Efficiency of Tunisian Water Distribution Utility. International Network and Spatial Economics. Feb 2022.

Abstract: This article has examined the operating cost inefficiencies and economies of scale of Tunisian public water services. We have examined the stochastic frontier model and the fixed effects model. Thus, as formulated, the inefficiency term remains in the model and the fixed effect is intended only to capture the firm-specific heterogeneity. Newly proposed true fixed-effects model appears to perform better than the panel data models in distinguishing between non-heterogeneity and inefficiency. The results indicate that significant cost inefficiencies are present in the utilities and economies of scale are found in small-sized utilities.

Tawfik Ben Amor (2022) Generalized Translog specification cost function to estimate drinking water Tarif: Case of Tunisia

Abstract: This study aims to estimate the marginal cost of the drinking water supply and analyze the implications for more efficient, equitable, and revenue-sufficient water rates in Tunisia. However, pricing in Tunisian water utilities has focused on setting water prices to cover average costs, usually using increasing block rate designs. This leads to a huge waste of drinking water. In an attempt to contribute to the efficient estimation of the pricing, model, we tried to introduce a multi-product Generalized Translog (GT) cost specification that incorporates Box-Cox transformation. Findings show that the marginal social costs of providing one m3 must be composed of a two-part tariff: volumetric charges of 0,048 euro/m3 and fixed connection charges of 0,055 euro/km.

4th February 2019, International conference "Information System and Intelligence" organized by the Higher School of Electronic Business of Manouba University and the University of Nancy and MohamedV Morocco. Marrackech (communication: Stochastic Models coefficients). Steering committee).

15 to– 16th November, 2017 The 1st American University in the Emirates International Research Conference (AUEIRC) scientific committee. (1st American University in the Emirates – International Research Conference (aue.ae))

March 2016 Conference IWCOman 2016 At University of Soltan Qaboos May 2006

May 2006 Research Seminar organized by the University of Alicante Spain. Visiting Professor Mr.Christophe Muller

2000 Seminar organized by the Laboratory of Applied Econometrics (Faculty of Management and Sciences Economiques Tunis Tunis) the work is titled borders multi-product and the measurement of technical efficiency. Case of ion production agriculture in Tunisia.