ارزیابی کارایی و بهره وری، رشد نسبی و بازرسی خودرو: استفاده از شاخص های تحلیل پوششی داده ها (DEA) و ملکوئیست (Malmquist)

The purpose of this paper is to analyze efficiency and productivity growth of the Norwegian Motor Vehicle Inspection Agencies for the period 1989–91. Efficiency measures are calculated by a non-parametric approach known as data envelopment analysis (DEA) which has particular applicability in the service sector. Productivity is measured by the Malmquist index and defined as the ratio between efficiency, as calculated by the DEA, for the same production unit in two different time periods. Total productivity growth has been found, but there is a variation among individual units. The observed total productivity can be accredited to decreasing input volumes and increased capacity. The main contributor to the observed total productivity growth is the frontier technical change effect which is found to be remarkably positive. The calculated efficiency measures show that there is, on the average, an input saving potential of 21–29% for the sector as a whole. The individual units are found to be rather unstable with respect to efficiency scores across the years of observation. The efficiency scores are not affected by the size of the units.

The relationship between motor vehicle accidents and compulsory vehicle inspection is well documented. Compulsory vehicle inspection, it is contended, is a necessary means of reducing road accidents. Little research has, however, been devoted to studies on the efficiency and productivity measurement of vehicle inspection services. This is the main concern of this paper. The underlying rationale is as follows: If vehicle inspections contribute toward reduction of road accidents, then improving the performance of vehicle inspection services would contribute toward the reduction of road accidents. Hence, the question that we pose is, are there any potentials for efficiency and productivity improvement in the vehicle inspection services, and if so, how can these potentials be achieved? In this paper we apply a new approach based on frontier production function to study productivity growth of the Norwegian Motor Vehicle Inspection Agencies. The framework is that of data envelopment analysis (DEA). The DEA approach defines a non-parametric best practice frontier and then measures efficiency relative to that frontier. The productivity growth of a unit (agency) can then be measured by a Malmquist index as improved efficiency relative to a benchmark frontier. The Malmquist indices for a sequence of years can consistently be chained and the resulting total productivity growth indices for each agency can be calculated as indices for frontier productivity growth and indices for catching up with the frontier. The main advantages of DEA that make it suitable for measuring the efficiency of vehicle inspection agencies are: (i) it allows the simultaneous analysis of multiple outputs and multiple inputs, (ii) it does not require an explicit a priori determination of a production function, (iii) efficiency is measured relative to the highest observed performance rather than against some average and (iv) it does not require information on prices. Since the Motor Vehicle Inspection Agencies are part of the public sector where economic behavior is uncertain and there is no price information on the services produced, the Malmquist index based on DEA approach is well suited for productivity measurement in this sector. The methodology has previously been applied in a number of industries to study productivity growth. Some recent applications have been to investigate the efficiency of Norwegian banking [1] and [2], to study the efficiency of Swedish public day care centers [3], to study the efficiency of Swedish hospitals [7] and to study the Swedish electricity retail distribution [14]. The remainder of this paper is as follows. Section 2 gives a brief summary of the organizational framework and objectives of the Motor Vehicle Inspection Agencies in Norway. Section 3 presents the methodology, i.e. DEA and the Malmquist productivity indices. Section 4 presents the data. In Section 5 the DEA and the decomposed Malmquist indices are applied and the results presented. Some managerial implications and ways of improving efficiency are discussed in Section 6. Concluding remarks are given in Section 7.

In this paper we have analyzed productivity growth in the Norwegian Motor Vehicle Inspection Agencies in the period 1989–91. The data comprise all the 67 units that form the sector. An approach which does not require price data or any specific economic assumptions about economic behavior has been applied. The framework is that of DEA piecewise linear frontier production function and the Malmquist index. Throughout the period of analysis, we find progress in total productivity. In terms of the individual units, however, we find a slowdown in productivity progress in the intermediate year, 1990–91. The decomposed index shows that much of the observed progress in total productivity is explained by the frontier shift term. There is a positive correlation between the catching-up effect and total productivity index. However, the catching-up effect is on the aggregate a decline in the periods 1989–90 and 1989–91. This has slowed down the pace of total productivity growth. In turn, the decline in the catching-up effect is due to the observed instability with respect to the efficiency measures. Reflecting on total productivity distribution, we find that these observations are a result of variation over the panel. Still, there are no systematic tendencies with respect to size. The calculated efficiencies show an input saving potential on the average of 21–29% throughout the sample period .With respect to efficiency measures it is also noted that the rate of instability across the years of observation is rather high. There is no simple explanation for the observed development in productivity. It should, however, be pointed out that 1990 was the year when the Road Traffic Plan for the period 1990–93 commenced. Traffic safety, which is the sole goal of the agencies, was pointed out as a major area for emphasis. It is, therefore, quite plausible that most of the agencies underwent some form of reorganization. This might have led to utilization of the idle capacity. Secondly, and probably most importantly, is that three years is rather too short a time for anyone to draw robust conclusions on the productivity performance of any sector. Nevertheless, the results presented here shed some light on the performance of the motor vehicle inspection sector as a whole. An obvious policy recommendation is to continue the registration of the activities carried out in all the units so that in the future, significant conclusions on the performance of the sector can be drawn. Secondly, using our results, decision makers should be able to identify the possible causes of inefficiency as well as decline in productivity within units. For decision makers it is important to know the units that define the frontier and their relative weights. This is because it is the relative ratio of “own” efficiency (catching-up effect) that explains total productivity development.