faced with sufficient clarity the reasons why other practitioners didn’t use it, which could have developed a product with wider appeal. “It was meaningful engagement with fewer users rather than having tons of people with access who never logged on, but I’d say we didn’t write that down ever as a philosophy or a plan…We didn’t really ever go along to the 50% who didn’t and say, why aren’t you, you know, it was up to them if they used it, they used it, they didn’t, they didn’t.” (Insight Bristol team) Also, this more organic approach to involvement meant that development activity wasn’t always systematically planned. For example, those in the Insight Bristol team describe user requirement validation processes as being somewhat informal: “We didn't look at any formal evaluation or anything like that. It was if we make a tool available and no one uses it, we know it doesn't work. If they use it, we know it works.” (Insight Bristol team) Whilst intensive engagement took place in the development of tools, thereafter some of those we talked to describe how this fell away with some aspects of the TFD, for example the development and iteration of the targeted risk models and strategic apps. This may in part explain why these elements showed less uptake than other elements of the TFD. “I had no involvement at all really with stakeholders after the [NEET] model was delivered. It was that phase that was missing.” (Insight Bristol team) “Maybe we just didn't work hard enough with the commissioning team to meet their needs, So maybe that's the gap.” (Head of Service) “The original Qlik app worked really well and actually it was really useful but then, there was changes done without my consultation.” (Early Intervention Manager) In addition, we found that not having a planned approa