What Do We Really Know? A 40-Year Scientific Realist Examination of Theory Testing in Project Management

Purpose: The nature and extent of middle-range theory testing, an indicator of intellectual progress, is an unexamined area in project management scholarship. Design/Methodology: We conducted a scientific realist analysis of all 4,033 articles published in three core project management journals over 40 years (1983 to 2023), and identified which theories were tested, how often, and their disciplinary origins. Findings: Theory testing grew from 6% to 33% of empirical articles. We found 19.5% theory testing density, comparable to neighboring disciplines. We identified 441 distinct theories tested and a large volume of single tests of domestic theories. However, repeatedly tested theories are predominantly borrowed from other disciplines, indicating reliance on foreign theories for knowledge creation. Practical Implications: We introduce a borrowed theory assessment framework and demonstrate its application to transaction cost economics, providing scholars and editors with criteria for evaluating foreign theories before adoption. Originality/Value: This is the first systematic examination of theory testing patterns in project management, revealing growing maturity and legitimacy while identifying overreliance on borrowed theories.