One of important steps to quality improvement of activities and increasing productivity in manufacturing systems, is noticing and emphasizing on evaluation factors that be Caused to personnel's efficiency reduction. Correct and timely recognition of factors that reduce to personnel's efficiency, especially managers, meets to efficiency improvement. One of major reasons of managers' efficiency reduction is dawdle. in this paper using descriptive statistics, Factor Analysis method and DEMATEL technique, has been purposed a novel model to analyzing existent similarities and diversities between opinions of different groups' managers of one company about reasons of dawdle, specifying and classifying most important areas that need to improvement, and specifying cause and effect relation between them. Findings this model show the most effective factor of dawdle and finally managers' efficiency reduction in office is very much visits and sessions with very little results, and least effective factor is be inordinate social. Also most causal factors are job incentive shortage, expert personnel shortage, mistake or incomplete information, and self assurance shortage.