Technology readiness levels: Shortcomings and improvement opportunities

The technology readiness level (TRL) scale was developed at the National Aeronautics and Space Administration (NASA) in the 1970s as a standardized technology maturity assessment tool for use in complex system development. Today, TRL assessments are used to make multimillion-dollar decisions at NASA and beyond, yet anecdotal evidence suggests that there are challenges associated with TRL use in practice. In this paper, we systematically uncover the practitioners' view, first via 19 interviews with employees from seven organizations. We identify 15 challenges of TRL implementations in three categories: system complexity, planning and review, and validity of assessment. Next, we prioritize these challenges via a survey of TRL practitioners, using a best-worst choice experiment. Finally, we identify best practices and proposed extensions to address the challenges. We find that system complexity challenges are most critical to TRL users, despite being addressed in the literature. We posit that addressing these opportunities could result in substantial improvements to decision processes and outcomes in complex engineering projects.