On the Role of Weight Restrictions in Data Envelopment Analysis

This paper examines the role that weight restrictions play in Data Envelopment Analysis (DEA). It is argued that the decision to include a factor (input or output) in a DEA model represents an implicit judgement that the factor has a non-trivial weight. It therefore seems perverse to allow DEA to assign a trivial weight to that factor in assessing the efficiency of a unit. There is therefore a strong case for imposing restrictions on factor weights. However, many existing methods of weight restriction are in practice unwieldy. This paper proposes an alternative approach we term contingent weight restriction which is both practical and intellectually consistent with the DEA philosophy. The paper explores the implications of alternative methods of weight restriction using simulated data from a well known production process.     

Does school ownership matter? An unbiased efficiency comparison for regions of Spain

The programme for international student assessment (PISA) 2006 Report (OECD, PISA 2006: science competencies for tomorrow’s world, Organisation for Economic Co-operation and Development, Paris in 2007) showed significant differences among Spanish students attending publicly financed schools. Publicly financed schools include entirely public schools and schools that are privately managed but publicly funded. Families with a lower socioeconomic status may self-select into public schools, so a direct efficiency comparison between the two school types could lead to flawed conclusions because of the possible school selection bias. In this paper, we suggest using a propensity score matching approach in order to correctly analyze the impact of school ownership on student performance. After tackling the self-selection problem, we use a stochastic parametric distance function framework to compare student efficiency and productivity in both school types across ten Spanish regions using PISA 2006 data. Furthermore, we propose two original measures to analyze the impact of school ownership on academic performance across regions: the average treatment effect on the treated on the production frontier and the average treatment effect on the treated assuming school inefficiency. We find that, on average, private government-dependent schools are more productive than public schools, although efficiency results across regions are highly divergent.     

Efficiency assessment of Portuguese municipalities using a conditional nonparametric approach

This paper assesses the efficiency of crop and livestock production in Colombia by using a sample of 1565 households. The study considers households located in different production systems which differ in geography, climate and soil types. These conditions affect technical efficiency and thus render analysis under the same production frontier as inadequate. For this reason, stochastic metafrontier techniques are preferred, allowing the estimation of technical efficiency within each production system and between production systems in relation to the sector as a whole. Results suggest that households in some production systems could be benefiting from better production conditions due to advantages in the availability of natural resources and climate as well as to more favorable socio-economic conditions. Additionally, we found that, in all systems, households with higher production have higher measures of technical efficiency. Thus, significant gains could be achieved in the sector through measures that contribute to improve the efficiency of households within their production systems and by policies that help reduce the technology gap in relation to the meta-frontier. These policies would bring positive impacts on the quality of life of small farmers and on the productivity of the sector.     

The impact of immigrant concentration in schools on grade retention in Spain: a difference-in-differences approach

Since the late 1990s, Spain has played host to a sizeable flow of immigrants who have been absorbed into the compulsory stage of the education system. In this article, our aim is to assess the impact of that exogenous increase in the number of immigrant students from 2003 to 2009 on grade retention using Spanish data from PISA 2003 and 2009. For this purpose, we use the difference-in-differences method as a dose treatment capable of detecting whether the immigrant concentration has had a significant effect on student performance. Our results evidenced that their arrival does not on average decrease school promotion rates with respect to 2003 and is even beneficial to native students. However, although the concentration of immigrant students at the same school does have a negative impact on immigrant students generating more grade retention, native students are unaffected until concentrations of immigrant students is above 15%.