7 June 2021
3 5 Scope of the document This document aims to define the key elements of a PTW and suggest metrics that can be used to help monitor the performance of your PTW system. [...] The document sets out: ■ general phases in the lifecycle of a PTW, and identifies potential metrics for each phase; ■ typical elements of a PTW but is not intended to provide a model for development of a PTW system. [...] The reason why elements are defined is not to help build a PTW system, but to show what the critical elements are and what they are trying to achieve in order to show the link to metrics. [...] Note: It can often be found that key performance indicators commonly used in the industry are really checklists for auditing the quality of the permit as opposed to checking the effectiveness of the system. [...] Even though the metrics are aligned to the part of the lifecycle that they are measuring performance of, the data to do that may not become available until a later stage.