When establishing the relationship between an external service provider (outsourcer) and customer, why do we document a whole operating model spanning both organisations? The whole point of outsourcing is that the supplier should be a black box, with inputs, outputs and performance requirements. What we need to define is the interface between the two entities, to ensure the operating models of each one mesh properly together: the Engagement Model. This is more efficient: we don't redundantly document processes which already exist, and are documented elsewhere. It is more effective: we focus on the gaps, specifying the requirements for change in each organisation in order to connect their operating models. This is pioneering stuff: there is very little published on what an engagement model should look like or how to develop and use it. Rob has built them: this presentation looks at a format, the content, and its uses