Where Is the Evidence of Performance Improvement in the Lean Construction Literature?

This paper critically evaluates the evidence of performance improvement within the lean construction literature.Through a systematic review of 1,351 papers presented at the International Group for Lean Construction (IGLC) conferences between 2013 and 2024, we identify a significant gap in evidence-based studies explicitly addressing performance improvement, with only 52 papers (3.8%) focus on this critical issue.Our findings highlight a predominant focus on building projects, while infrastructure and industrial sectors remain largely overlooked.Additionally, we classify the various performance metrics used in the literature, revealing a lack of standardisation in measuring project outcomes, which complicates benchmarking efforts.We advocate for the adoption of a consistent performance measurement framework to enable meaningful comparisons across similar projects, facilitating the identification of performance improvement and waste reduction.We argue that a structured, industry-wide approach to benchmarking and performance evaluation is essential for the sustained adoption of lean construction and the realisation of its full benefits.