Shahid Beheshti University Journal of Industrial Management Perspective 2251-9874 2 4 2013 02 19 Checking the Performance Changes of Distribution Channels of Pars Khazar Company over Time using Window Analysis Checking the Performance Changes of Distribution Channels of Pars Khazar Company over Time using Window Analysis 167 183 87333 FA Mohammad Rahim Ramazanian Associate Professor, Guilan University. Reza Esmaeilpour Assistant Professor, Guilan University. Keikhosro Yakideh Assistant Professor, Guilan University. Akram Oveysi Omran MA Student, Guilan University. Sahar Majlessi MA Student, Guilan University. Journal Article 2019 09 29 <span lang="EN">Window analysis basically assumes that no technical change has taken place in the periods under review. This underlying assumption has been neglected in most research works. In the current study, using non-parametric statistical Wilcoxon test and Friedman test between two time periods and over two time periods, the shift frontier between the periods under review has been investigated and determined. </span>Accordingly, <span lang="EN">the length of the windows was selected in the way that the basic assumption of window analysis was observed. In this research, the data of </span>7 distribution-channels of Pars Khazar Company <span lang="EN">was picked up in time periods of one year (2005-2011). After running the statistical tests, it was revealed that shift frontiers had occurred within the periods (2007 and 2008), (2008 and 2009) and (2010 and 2010). So four analyses with the lengths of 3, 1, 2, and 1 were performed in which the average performance of the units was obtained as 0.832, 0.987, 0.906 and 0.953, respectively.</span><span lang="EN"> </span> <span lang="EN">Window analysis basically assumes that no technical change has taken place in the periods under review. This underlying assumption has been neglected in most research works. In the current study, using non-parametric statistical Wilcoxon test and Friedman test between two time periods and over two time periods, the shift frontier between the periods under review has been investigated and determined. </span>Accordingly, <span lang="EN">the length of the windows was selected in the way that the basic assumption of window analysis was observed. In this research, the data of </span>7 distribution-channels of Pars Khazar Company <span lang="EN">was picked up in time periods of one year (2005-2011). After running the statistical tests, it was revealed that shift frontiers had occurred within the periods (2007 and 2008), (2008 and 2009) and (2010 and 2010). So four analyses with the lengths of 3, 1, 2, and 1 were performed in which the average performance of the units was obtained as 0.832, 0.987, 0.906 and 0.953, respectively.</span><span lang="EN"> </span> https://jimp.sbu.ac.ir/article_87333_9537f91d30adfdcf63eedbb95e181092.pdf