Multidimensional inequality comparisons: A compensation perspectiveJournal articleChristophe Muller and Alain Trannoy, Journal of Economic Theory, Volume 147, Issue 4, pp. 1427-1449, 2012

We provide a unified treatment of the two approaches pioneered by Atkinson and Bourguignon (1982, 1987) [3,4] by resorting to compensation principles in the bivariate case. We treat the attributes of individual utility asymmetrically by assuming that one attribute can be used to compensate another. Our main result consists of two sufficient second-order stochastic dominance conditions. In the case where the compensated variable has a discrete distribution, the distribution of the compensating variable must satisfy a condition which degenerates to the Sequential Generalized Lorenz test for identical marginal distributions of the compensated variable. Furthermore, the distributions of the compensated variable must satisfy the Generalized Lorenz test.

Demographic transition, education and economic growth in TunisiaJournal articleOlfa Frini and Christophe Muller, Economic Systems, Volume 36, Issue 3, pp. 351-371, 2012

This paper provides empirical evidence supporting the interaction between fertility, education and economic growth through the underlying mechanism behind that correlation in accordance with Becker's theory. In consistency with the theory, the key explanatory variables in Tunisia's fertility model are real GDP per capita, infant mortality, contraceptive use ratio, and education. As opposed to most empirical works, the present study takes into consideration three educational levels, i.e., primary, secondary and higher. Also unlike most empirical research, this study attempts to analyse the impact of fertility transition on education and economic growth. To deal with too little or incomplete data, time series data for Tunisia are computed over 45 years. A multivariate cointegration analysis is carried out and shows that a long-term triangular relationship exists. A short dynamic run analysis based on the vector correction error model displays results in coherence with and close to those of the long term. Among our key results, education is found to trigger fertility transition both in the short and long run. In addition, education has relatively fostered economic growth but hardly boosted it through its dynamic interaction with fertility. Furthermore, the variance decomposition and the impulse function show that the fertility transition has produced a feedback effect on both education and economic growth.

Within-Firm Human Capital Externalities in TunisiaJournal articleChristophe Muller and Christophe Nordman, The Journal of Development Studies, Volume 47, Issue 4, pp. 657-675, 2011

This case study exploits matched firm-employee Tunisian data in order to underline the role played by within-firm human capital in worker remuneration. The estimated returns to human capital in wage equations remain unchanged when the dummies representing firm heterogeneity are replaced in the list of regressors with three firm variables: a textile industry dummy, within-firm mean education, and firm age. We find that part of what is usually considered as return to education may be due to within-firm externalities.

A dominance approach to the appraisal of the distribution of well-being across countriesJournal articleChristophe Muller and Alain Trannoy, Journal of Public Economics, Volume 95, Issue 3-4, pp. 239-246, 2011

This paper proposes a dominance approach to study inequality of well-being across countries. We consider a class of well-being indices based on the three attributes used in the HDI (Human Development Index). Indices are required to satisfy: preference for egalitarian marginal distributions of income, health and education, ALEP substitution of attributes and priority to poor countries in allocating funds to enhance health and education. We exhibit sufficient conditions for checking dominance over the defined class of well-being indices. We apply our method to country data from 2000 to 2005. The deterioration in health conditions in poor countries is why welfare improvements at the world level cannot be ascertained.

Incentives and Survival in Violent ConflictsJournal articleMoshik Lavie and Christophe Muller, Goettingen Journal of International Law, Volume 3, Issue 1, pp. 155-174, 2011

This paper analytically investigates the incentive scheme of perpetrators of violent conflicts. It provides a rational equilibrium framework to elicit how monetary incentives and survival considerations shape a combatant’s decision to participate in a conflict. In the model, a leader decides to award soldiers monetary incentives. Civilians finance the militia via donations and soldiers decide on the actual fighting and indulge in looting. We explore the scheduled decision-making that takes place on the path toward a violent conflict and study the principal–agent relationship that exists between the leader and the militia. In addition, we analyze the effect of several internal factors (productivity and survival risk) and external factors (relative economic resources, opponents’ military strength) on the intensity of the conflict.
The model shows that soldiers fighting decisions are set by personal mortality risk and the level of identification with the cause of war. In addition, our results link between monetary incentives and participation in fighting and demonstrate a substitution effect of looting and donations as monetary incentives.

Anti-Poverty Transfers and Spatial Prices in TunisiaJournal articleChristophe Muller, Journal of Development and Economic Policies, Volume 12, Issue 2, pp. 85-113, 2010

In this paper, the role of price deflation in estimating the impact of price subsidies and anti-poverty
cash transfer schemes on poverty in Tunisia is studied. Three types of price corrections are considered: (a) no
corrections; (b) living standards deflated by spatial Laspeyres price indices; and (c) living standards deflated
by true price indices that are estimated from a quadratic almost ideal demand system. Distinguishing these
corrections and using data from Tunisia, the effects of the price deflation and the demand system estimation
on poverty and budget leakage estimates are analyzed. These effects can intervene at two stages of the
estimation: (a) the calculation of transfer levels for each household; and (b) the estimation of post-transfer
social statistics.
Results show that price correction, whatever its form, may have only limited importance
for the assessment of anti-poverty policy in Tunisia. Correcting or not for spatial price differences, or
for consumption substitution does not modify the performance ranking of the studied policies. This is
at odds with other findings in the empirical literature that price differences may be important for poverty

Application of Stochastic Production Frontier in the Estimation of Technical Efficiency of Irrigated Agriculture in TunisiaJournal articleTawfik Ben Amor and Christophe Muller, Agricultural Journal, Volume 5, Issue 2, pp. 50-56, 2010

In this study, we estimate agricultural technology for Tunisian peasants, accounting for the crop choice of perasants and distinguishing inputs for individual crops such as: vegetable farming cereal and fruit-trees. The study employed the use of cross-section data from distinguishable irrigated crops survey conducted on a sample of 218 farmers frome 11 regions in Tunisia. The data were collected with the aid of structured questionnaire and were later analysed. The Cobb Douglass production frontier model is employed in order to analyse data collected. Among the irrigated crop farmers, the significant variables were: farmuar manuar fertiliser quantity, labor, mecanic traction and among of irrigated water applied. The estimated sigma square (σ2) and gamma (γ) are widely significants for all irrigated crops and revealed that >85% of the variation in the Tunisian irrigated output among farmers in the study area are due to the differences in their efficiencies. Howerver, 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 on inefficiency effects among the farmers as: education, farmer’s age, irrigation techniques, lack of education, property of land.

Refining Targeting against Poverty Evidence from TunisiaJournal articleChristophe Muller and Sami Bibi, Oxford Bulletin of Economics and Statistics, Volume 72, Issue 3, pp. 381-410, 2010

We introduce a new methodology to target direct transfers against poverty. Our method is based on estimation methods that "focus on the poor". Using data from Tunisia, we estimate 'focused' transfer schemes that highly improve anti-poverty targeting performances. Post-transfer poverty can be substantially reduced with the new estimation method. For example, a one-third reduction in poverty severity from proxy-means test transfer schemes based on OLS method to focused transfer schemes requires only a few hours of computer work based on methods available on popular statistical packages. Finally, the obtained levels of undercoverage of the poor are particularly low. Copyright (c) Blackwell Publishing Ltd and the Department of Economics, University of Oxford, 2010.

Do agricultural outputs of partly autarkic peasants affect their health and nutrition? Evidence from RwandaJournal articleChristophe Muller, Food Policy, Volume 34, Issue 2, pp. 166-175, 2009

In rural areas of less developed countries because of market imperfections, the health and nutritional status of peasants may directly depend on the production levels of specific agricultural goods rather than solely on income levels. This channel of health and nutrition determination has never been studied. In order to assess and test the empirical possibility of this channel, we estimate the responses of health and nutritional status of autarkic agricultural households in Rwanda with respect to differences in socio-demographic characteristics and the main agricultural outputs and inputs while controlling for local environment and sampling scheme. Several food outputs are found to have a positive influence on health and nutrition, whereas the production of traditional beers has a negative impact. Moreover, greater land negatively affects health and nutrition, conditionally on agricultural production, perhaps because of a larger relative workload for households who have a large farm. An alternative interpretation of the estimates is that they inform on the validity of the common hypothesis of perfect agricultural input/output markets with no effect of agricultural inputs/outputs on health and nutrition status. This hypothesis is rejected.

The Measurement Of Poverty With Geographical And Intertemporal Price Dispersion: Evidence From RwandaJournal articleChristophe Muller, Review of Income and Wealth, Volume 54, Issue 1, pp. 27-49, 2008

It is not known to what extent welfare measures result from seasonal and geographical price differences rather than from differences in living standards across households. Using data from Rwanda in 1983, we show that the change in mean living standard indicators caused by local and seasonal price deflation is moderately significant at every quarter. By contrast, the differences in poverty measures caused by this deflation can be considerable, for chronic as well as transient or seasonal poverty indicators. Thus, poverty monitoring and anti-poverty targeting can be badly affected by inaccurate deflation of living standard data. Moreover, when measuring seasonal poverty, the deflation based on regional prices instead of local prices only partially corrects for spatial price dispersion. Using annual local prices instead of quarterly local prices only yields a partial deflation, which distorts the measure of poverty fluctuations across seasons and biases estimates of annual and chronic poverty. Copyright 2008 The Authors.