Overall Task Effectiveness : a new Lean performance indicator in engineer-to-order environment

Purpose: The purpose of this paper is to propose a new Lean metric named Overall Task Effectiveness (OTE), which can help analyst to define target task times and to identify the hidden losses that account for most of the recorded time of manual assembly activities. Design/methodology/approach: An alternative classification structure of the losses is developed to divide them in two classes. In the first one the losses that are external to the project order are included, and in the other one those due to inefficiencies directly ascribable to the project order are considered. Starting from this classification structure of the losses, a novel Lean metric, inspired from the well-known Overall Equipment Effectiveness (OEE), is developed to evaluate the effectiveness of a manual assembly task. A case study, which briefly explains the methodology and illustrates the capability of the corresponding metric, is provided. Findings: This tool can be considered a suitable method to achieve simultaneously a dual purpose to establish time standards and to identify the hidden losses that account for most of the recorded time of manual assembly activities, estimating the impacts of potential corrective actions in terms of both efficiency and effectiveness. Practical implications: OTE provides practitioners with an operative tool useful to highlight the points where the major inefficiencies take place in industries producing large complex items via manual assembly lines. Its practical application is demonstrated using a case study concerning a manufacturer of train wagons. Originality/value: One distinctive, and contemporarily appealing, feature of OTE with respect to other analogous KPIs is that it provides a breakdown structure for process losses that simplifies the task of evaluating the current performances and, at the same time, individuates both the source of losses and the corresponding corrective actions.