<![CDATA[The success of a construction project is determined not only by technical aspects but also by the project manager’s leadership in managing resources and controlling project costs. This study aims to identify the variables that influence project manager leadership on the performance of the Underground Tank Construction Project at PT Panasonic and to determine the most significant variable affecting project performance from the cost perspective. The research employed a descriptive quantitative method, with data collected through questionnaires distributed to 40 respondents involved in the project implementation. The independent variables consisted of communication, decision-making, coordination, technical competence, and problem-solving, while project cost served as the dependent variable. The data were analyzed using descriptive analysis, percentage analysis, and mean score calculations with the assistance of Microsoft Excel. The results indicate that all variables influence project performance in terms of cost, with mean scores of 3.27 for communication, 3.27 for decision-making,3.26 for coordination, 3.16 for technical competence, and 3.29 for problem-solving. Problem-solving was identified as the most significant variable affecting project performance, as it achieved the highest mean score. The findings demonstrate that a project manager’s ability to effectively identify, analyze, and resolve project issues plays a crucial role in controlling project costs and supporting successful project implementation.]]>
