The study addresses the growing demand for evidence-based methods to assess the effectiveness of project managers in engineering-intensive industries. An exploratory competency model was developed in a German automotive R&D service division, integrating both behavioral and technical dimensions into a quantifiable measure termed the competency coefficient (K). Ten project managers, classified as either superior or average performers, were evaluated across 20 individual competencies. Behavioral Event Interview (BEI) results revealed substantial differences between the two groups, with effect sizes exceeding d = 2.0 for competencies such as concern for order, customer orientation, and impact and influence, while core cognitive competencies Analytical thinking (AT), conceptual thinking (CT), information seeking (INFO) demonstrated significant but more variable effects (d = 1.2–2.0). Expert panel evaluations (n = 33) showed strong consensus (Kendall’s W = 0.59, p <.001), with average relevance scores above 80%. Sensitivity analyses of alternative weighting schemes for the K metric (e.g., 3–2–1; 4–2–1; 5–3–1) yielded highly stable rankings (Spearman’s ρ ≥ 0.97), indicating robustness of the results. Initial validation against project performance indicators suggested significant positive correlations (r = 0.65–0.88, p <.01) between K values and Key Performance Indicators (KPIs). Within the examined automotive R&D division, the findings suggest that individual competencies—particularly cognitive and INFO skills—were the most distinctive differentiators of high-performing project managers, whereas technical expertise alone did not explain performance differences. The competency coefficient provides a structured, quantifiable framework for linking competencies to project outcomes, though further validation across broader datasets and organizational contexts remains necessary.