Publications > Cahiers (English)> N° 67, 2nd term 2003

• R&D, technology and productivity growth in Italian agriculture, 1963-1991,
  R. ESPOSTI, P. PIERANI
  
• Innovation adoption in agriculture : innovators, early adopters and laggards,
  P. DIEDEREN, H. van MEIJL, A. WOLTERS, K. BIJAK texte au format PDF
  
• Le couplage des modèles agronomiques et économiques : intérêt pour l'analyse des politiques, G. FLICHMAN, F. JACQUET
  [Integrating agronomic and economic models for agricultural policy analysis]
  

  METHODES

• Evaluation de la précision d'estimateurs de fonctionnelles : l'exemple de la consommation alimentaire, P. BERTAIL, C. BOIZOT, P. COMBRIS
  texte au format PDF
  [Precision performance of functional estimators : the case of food consumption]
  

COMPTES RENDUS DE LECTURE

M.-U. PROULX, L'économie des territoires au Québec : aménagement - gestion - développement, by M. Polèse ; B. LOMBORG, The Skeptical Environmentalist. Measuring the Real State of the World, by D. Vermersch

R&D, technology and productivity growth in Italian agriculture, 1963-1991

Roberto ESPOSTI*, Pierpaolo PIERANI** (* Department of Economics, University of Ancona, Piazzale Martelli 8, 60121 Ancona, Italy. e-mail : robertoe@deanovell.unian.it - ** Department of Economics, University of Siena, Piazza S. Francesco 7, Siena, Italy. e-mail : pierani@unisi.it)

In : Cahiers d'Economie et Sociologie Rurales, n° 67, 2003, pp 5-27

Summary - This paper investigates the role of gross investments in Research and Development (R&D) and, in extension, in generating technical change by adding a variable representing the knowledge stock in a cost function of Italian agriculture. It is a short-run cost function thus regarding only variable factors while other conventional inputs are considered fixed. The chosen functional form (translog) belongs to the family of flexible functions and allows an estimation of the technology parameters without imposing any restriction on the factor substitution matrix both in the short and in the long run. Moreover, it is possible to measure the biases and the rate of technical change as well as the rate of return to R&D-extension public expenditure. The model can provide empirical evidence of the positive and relevant impact of these investments on Italian agricultural productivity net of scale effect and capacity utilization.

Key-words : Italian agriculture, R&D expenditures, cost function.

Innovation adoption in agriculture : innovators, early adopters and laggards

Paul DIEDEREN*, Hans van MEIJL*, Arjan WOLTERS**, Katarzyna BIJAK*
(* Wageningen University and Research Centre, Agricultural Economics Research Institute (LEI), P.O. Box 29703, 2502 LS The Hague, The Netherlands. e-mail : Paul.Diederen@wur.nl - J.C.M.varMeijl@LEI.DLO.NL - K.H.Bijak@LEI.DLO.NL - ** Dutch Ministry of Economic Affairs, P.O. Box 20101, 2500 EC The Hague, The Netherlands. e-mail : A.M.Wolters@minez.nl)

In : Cahiers d'Economie et Sociologie Rurales, n° 67, 2003, pp 29-50

Summary - This paper analyses the choice of a farmer to be an innovator, an early adopter or a laggard (an adopter of mature technologies or a non-adopter) in the adoption of innovations that are available on the market. We estimate a nested logit model with data from a large sample of Dutch farmers. We find that structural characteristics (farm size, market position, solvency, age of the farmer) explain the difference in adoption behaviour between innovators and early adopters on the one hand and laggards on the other. We also find that early adopters and innovators do not differ from each other regarding these structural characteristics. However, they appear to differ in behavioural characteristics : innovators make more use of external sources of information and they are more involved in the actual development of innovations.

Key-words : innovation, adoption, nested logit model, agriculture, The Netherlands.

Le couplage des modèles agronomiques et économiques : intérêt pour l'analyse des politiques
[Integrating agronomic and economic models for agricultural policy analysis]

Guillermo FLICHMAN*, Florence JACQUET* (* CIHEAM-IAMM, UMR Lameta, 3191, Route de Mende, 34093 Montpellier cedex 5. e-mail : g.flichman@wanadoo.fr - e-mail : jacquet@iamm.fr)

In : Cahiers d'Economie et Sociologie Rurales, n° 67, 2003, pp 51-70

Summary - Integrating agronomic and economic models falls within the realm of bio-
economic models whereby biological processes under study are explicitly represented. In the case of agriculture, this approach is based, on the one hand, on an agronomic model specification of production technologies integrated to an economic model – most often of a constrained optimisation type – and on the other hand, on their impacts in terms of yields and environmental externalities. This explicit (primal) representation of technologies is well suited to study the environmental impacts of agricultural policies and represents an interesting alternative to the dual approach that is frequently used in the econometrics. It also enables ones not only to assess the effects of new agricultural policy instruments such as decoupled subsidies and agri-environmental contracts but also to take into account the non-convexities between agriculture and the environment.

Key-words : environment, agricultural policy, bioeconomic model, agronomy.

Evaluation de la précision d'estimateurs de fonctionnelles : l'exemple de la consommation alimentaire
[Precision performance of functional estimators : the case of food consumption]

Patrice BERTAIL*, Christine BOIZOT**, Pierre COMBRIS** (* CREST, LSA, J340, 3 avenue Pierre Larousse, 92405 Malakoff et INRA, CORELA, 65, Bd de Brandebourg, 94205 Ivry sur Seine. e-mail : Patrice.Bertail@ensae.fr - ** INRA, CORELA, 65, Bd de Brandebourg, 94205 Ivry sur Seine. e-mail : boizot@ivry.inra.fr - combris@ivry.inra.fr)

In : Cahiers d'Economie et Sociologie Rurales, n° 67, 2003, pp 71-101

Summary - This paper proposes several methods for computing precise confidence intervals or evaluating the precision of some statistics related to individual food consumption, based on complex household food survey datas. We show how it is possible to obtain asymptotic confidence intervals for non-linear functionals thanks to the delta method and the notion of Hadamard differentiability. However asymptotic confidence intervals may not be very precise and to not take into account the dissymetries of the statistics or the underlying distributions. We develop two different methods based on resampling ideas to obtain precise confidence intervals. The first one is a transposition of the weighted bootstrap to survey sampling. The second uses the universal properties of subsampling and extrapolation methods to obtain rapidly accurate results. We compare and apply these methods to the construction of confidence intervals for means, fractiles, dispersion indexes of individual food consumptions (with or without null consumptions). We apply these methods to several products from the 1994 Secodip french panel.

Key-words : Hadamar differentiability, bootstrap, consumption survey, confidence intervals.