Efficiency measurement by DEA window analysis method in cement factories

Cement sector has reached the position of a rapidly growing sector specially in developing countries such as Turkey in recent years. With the effect of the increasing population, the need for housing and infrastructure contributed to the growth of the cement sector. Turkey has been among the countries that have shown a successful performance in meeting both domestic and foreign demand in the cement sector. Considering both the increase in international competition in the sector and its economic and social effects for the country, the performance of cement companies should be evaluated regularly. In this study, the efficiency change of 12 cement companies listed on Borsa Istanbul (BIST) between the years 2015-2022 was measured by using CILOS and Data Envelopment Analysis (DEA)-Window Analysis methods in combination. In the first stage of the two-stage application, the input and output variables to be used in DEA were determined by the CILOS method, which is an objective MCDM technique. In this way, subjective and time-consuming judgments of decision makers are avoided. In the following stage, the dynamic efficiency of cement companies was measured with the DEA-Window analysis method using these variables. According to the results obtained, it has been observed that the efficiency in cement companies fluctuates over time and there is no trend in a certain direction. In other words, the companies analyzed did not show a stable performance. It is seen that the worst performance occurred in 2021 with the effect of the Covid-19 pandemic. In 2022, companies performed well with the decrease of the pandemic effect. This study is one of the rare studies in which the efficiency change in the cement sector is measured through the DEA-Window analysis method. The integrated CILOS-Window analysis method proposed for the first time in the literature is a practical technique that can also be used to measure the efficiency changes of other organizational units.