###### Abstract  
The research question this study poses is how to measure the efficiency of project management activities. The purpose of this article is to quantify the efficiency of the execution of a project portfolio managed by a project management office (PMO) structure. The research subject is a PMO operating within a petrochemical manufacturing company in southern Brazil. The research method is quantitative modeling. The study employed data envelopment analysis (DEA) to calculate the relative efficiencies of projects in three classes according to complexity over a period of four years. Each project is a decision-making unit (DMU), as required by the DEA procedure. One novelty is the calculation of cost- and time-weighted efficiency values, which slightly differ from the average. The main results indicate that the average efficiency for classes of projects roughly stands between 40 and 80%. The results also indicate a learning process guided by the PMO, as the average efficiency increased over three years in two classes of projects, according to the prioritization imposed by the office. The study also pointed out that the most influential variables in determining project efficiency are accuracy in meeting deadlines and the time planned for completion. The most important implication is that, from now on, the company has a theoretical foundation to justify focusing further efforts on reducing and controlling time to completion, not only cost and scope conformity, to increase overall project efficiency. Future research should prioritize investigating management techniques that increase the likelihood of completing projects within their deadlines. p 2024 7 2024  
Office (PMO). The PMO's primary role encompasses critical project functions, including defining governance protocols, resource allocation planning, and assessing interim and overall outcomes [6]. Additionally, the PMO is responsible for adhering to business constraints [7] and ensuring alignment with the operational strategy [8]. Companies that adopt a PMO-type structure tend to achieve heightened efficiency in project execution [9]. Authors like [7; 10; 11; 12] delve into aspects related to project efficiency. Assessing a project's efficiency involves considering the resources employed during execution and the outcomes achieved upon completion compared to the optimal utilization of resources and the maximal output generation benchmark. However, such comparative assessments encounter limitations because benchmarking analyses are typically external, involving comparisons with similar projects carried out by competitors [13]. An appealing alternative is internal benchmarking, where projects executed by the same organization are compared [14]. In internal benchmarking, each project led by the Project Management Office (PMO) is a decision-making unit (DMU) for comparisons with other projects sharing similar attributes, either over time or longitudinally. Data Envelopment Analysis (DEA) evaluates a DMU, such as companies or projects, by employing multiple inputs and outputs, which facilitates the identification of best practices and promotes organizational learning [15]. A Scopus database search in October 2023 yielded 5935 articles, published between 2017 and 2023, containing the phrase \"project management efficiency\" in both the title and as a keyword. Subsequently, a second search identified only three articles during the same period in the same database, featuring \"project management efficiency\" in the title and the keyword \"efficiency.\" These findings suggest that examining efficiency in project execution within the domain of PM still needs to be explored in existing research. This is the research gap the study aims to bridge. The research question posed is how to measure the efficiency of PM activities. The purpose of this article is to quantify the efficiency of the execution of a project portfolio managed by a project management office (PMO) structure.