Architectural plan-checking reports which are produced and archived day by day in the broad range of local offices of the Iran Construction Engineering Organization (IRCEO) throughout the country, can provide a reliable picture of the general condition of architectural design services in each office’s territory and the whole country in general. However, there have been no proper attention given to these reports as a resource to extract indicators relating to the quality of building design services provided by the relevant architectural firms. The current research is an attempt to fill this gap through which a method is suggested to analyze and interpret the plan-checking reports. To this purpose, as a case study, the method is applied to the plan-checking reports produced in the Rasht office of the IRCEO during March 2017 to December 2017. Meanwhile, 1821 files have undergone the plan checking process among which 954 ones (52%) were rejected by the architectural control officials in their first checking of the documents. Among these rejected files as the total population 419 ones were selected as the sample according to the Cochran formula. In order to achieve an analysis of the content of the reports, the control officials’ rejection comments on each project were categorized into four main categories including comments related to in-complete application file, improper drafting properties, inner incompatibility of the project plans, and non-conformance to technical requirements which were subdivided into sub-categories in turn.

Based on this the most frequent rejection comments were as follows: drafting-related defects 49.5%, non-compliance with the Iranian national building codes 15%, discrepancy between architectural and structural plans 10%, non-compliance with the extra technical requirements of the local office of the IRCEO 7% and the defects based on the architectural control official’s discretion 6.5%. In the next step, some statistical patterns were extracted from the reports, which comprised seven patterns. In order to analyze the statistical findings and achieve a reliable interpretation of the patterns, interviews were conducted with eight principals of architectural firms in Rasht. Finally, the patterns observed in architectural control reports were interpreted and their causes and suggested solutions were discussed. Each provincial office of the IRCEO can target specific indicators according to its architectural firms’ conditions and, over time, improve its architectural design services standards. This paper ends up with a critique of the idea of abandoning the plan checking from the new suggested building control bylaw.