دانلود رایگان مقاله بازنگری: بهره وری پویا در صنعت آب و فاضلاب انگلیسی و ولز

Abstract

The English and Welsh water and sewerage industry is characterised by indivisible capital which has a long service life. Previous studies of efficiency for the English and Welsh water and sewerage industry take a static framework, assuming all inputs can be adjusted instantaneously. This paper measures dynamic efficiency by incorporating intertemporal links of capital within the production function for the English and Welsh water and sewerage industry for the period 1997–2011. Dynamic Data Envelopment Analysis (DEA) considers capital as a quasi-fixed input and is modelled as a contemporaneous output into current production and an input from past production. The results show that the inadequate intertemporal allocation of quasi-fixed inputs is the largest contributor of inefficiency.

7. Conclusion

This paper has evaluated the effect of dynamic DEA in the English and Welsh water and sewerage industry. A two output model has been constructed for the ten WaSCs within the industry for the period 1996/97–2010/11. Environmental variables have been considered within the analysis in order to account for those firms that operate under relatively favourable or unfavourable environments. The estimates show that the main estimated inefficiencies are due to the quasi-fixed inputs. The overall first stage inefficiencies within the industry range from 0 to 22.2%. The optimality conditions show the persistent over-utilisation of quasi-fixed inputs. Our results indicate that the inefficiencies from variable inputs have improved over the period, whereas those from capital stock remain persistent. These results are consistent may be due to the different incentive rates between opex and capex and the Averch– Johnson effect created by the presence of rate of return regulation. Overall the results infer the presence of a capex bias within the industry.