## 4 Conclusions
The systematic identification, validation, and functional mapping of Lean tools provide a foundation that can be adapted to other design contexts and project types. Moreover, the insights obtained through expert involvement and tool interaction analysis offer a long-term reference for practitioners and academics seeking to implement or refine Lean Design strategies. This study opens avenues for future research, including longitudinal case studies to evaluate the actual impact of tool combinations over time, the integration of digital platforms for Lean Design monitoring, and the exploration of Lean-BIM-Agile synergies in diverse construction environments. This study presents several limitations that should be acknowledged. First, the analysis of the relationship between Lean tools and their associated functionalities was based on binary mappings validated through expert consensus rather than continuous numerical ratings. As a result, advanced multivariate techniques, such as Principal Component Analysis (PCA), factor analysis, or Structural Equation Modeling (SEM), could not be applied within the current methodological framework. Future research should consider the development of a structured survey instrument that captures quantitative assessments of the degree to which each tool supports specific functionalities, allowing the use of dimensionality reduction methods and statistical modeling to strengthen explanatory power. Second, although four new Lean tools were incorporated based on expert recommendations, no evidence regarding their specific benefits or drawbacks was found in the literature or mentioned by the consulted experts. Additionally, not all benefits and limitations reported in the literature for the twelve previously known Lean tools were validated during the expert consultation phase, which may limit the completeness of the functional assessment. Third, the qualitative validation component was constrained by a reduced number of participants. Although the original plan involved interviewing five professionals per design role, only fifteen design professionals were ultimately consulted through semi-structured interviews. This smaller-than-expected sample may affect the generalizability of the findings and highlights the need for broader practitioner engagement in future validation studies. Furthermore, although the study included participants from diverse professional backgrounds, it did not statistically examine whether roles such as architects, engineers, or consultants perceive the advantages and disadvantages of Lean tools differently. Future research could apply inferential techniques, such as Chi-square tests or logistic regression models, to analyze whether professional profile significantly influences the perception and adoption of tools like BIM, LPS, or ADM. Incorporating this type of analysis would enrich the understanding of sociotechnical barriers and accelerators in the practical implementation of Lean-based design management. Finally, this study did not explore in depth the interaction between complementary tools, such as BIM-LPS or BIM-ADM, in practical design environments. Future research should investigate these interactions through longitudinal case studies or pilot implementations to evaluate their combined impact on collaboration, decision-making, and value generation in the building design process. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15095137/s1](https://www.mdpi.com/article/10.3390/app15095137/s1)]([https://www.mdpi.com/article/10.3390/app15095137/s1](https://www.mdpi.com/article/10.3390/app15095137/s1)), Supplementary Material. Informed consent to participate in an interview for the development of a research project. **Author Contributions:** Conceptualization, R.F.H. and K.C. ; methodology, R.F.H., K.C. and C.B. ; software, A.L. ; validation, R.F.H., K.C. and C.B. ; formal analysis, A.L. ; investigation, A.L. ; resources, A.L. ; data curation, E.A. ; writing--original draft preparation, A.L.