**6. Conclusions**

Enhanced productivity is an overarching goal in the construction sector as it integrates the effectiveness and efficiency of project's resources while guaranteeing the quality of the work. This paper explores, for the first time, qualitative evidence for the interdependencies between the equipment operator's performance and the construction equipment's productivity. Through an extensive literature review and interviews with experts, this paper was challenged to provide an annotative approach and pave the way for further constructive thinking on the examined topic.

This research objective was to: (i) recognize the factors affecting operators' performance levels that are closely related to a project's productivity and (ii) prioritize those factors by attributing total scores with Transparent Choice's tool for the AHP. The AHP was selected as the most suitable method for this research by utilizing its ability to weight and hierarchize the criteria, without the need to specify alternative attributes. The factors were divided into two groups, subjective and objective, and each group included two and three categories, respectively. On level three of the decision tree model twenty-one factors were investigated and shortlisted using the AHP. The decision tree model was evaluated by

different types of evaluators, such as academia, equipment owners, operators, and project managers. Each group of evaluators formed a different profile by attributing different total scores to each criterion. The academia group was the group of evaluators that presented similar results to the cumulative ones and similar profiles to the operators' group. The operator's competence was considered by all groups of evaluators as the most important factor; in particular, "knowledge" and "experience" ranked first, followed by "training" and "on-site preparation" and contributed radically to the construction equipment operators' performance.

The limitations of this research relate to the fact that this was the first holistic approach to relating the equipment operators' performance with the tangible and intangible factors identified in the literature and expert interviews. More experts could surely enhance the robustness of our results. Moreover, in future research, the qualitative approach presented here could be expressed in mathematical equations in order to quantify the sensitiveness of the factors analyzed in relation to the equipment's productivity.

**Author Contributions:** Conceptualization, K.P.; Data curation, K.T.; Formal analysis, I.L.; Investigation, K.T.; Methodology, K.P. and I.L.; Project administration, K.P.; Software, I.L. and K.T.; Supervision, K.P.; Writing—original draft, I.L. and K.T.; Writing—review & editing, K.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors would like to acknowledge the significant contribution made by the evaluators, without whose valuable input and support the quality of this work could not be ensured.

**Conflicts of Interest:** The authors declare no conflict of interest.
