Interaction between product manager and usability expert

The product manager plays a role throughout the product development or the projectexecution cycle. The product manager delivers requirements, discusses them with the feature teams, collaborated and provides clarifications during the design phrase and also plays a key role during the development and testing cycles - defining what the flow for the feature should be case there is a lack of clarity among the development team (and there will typically be some small part or element of the workflow or the screens or the UI that may not have been well detailed during the requirements or design process and needs the inputs of the product manager); in addition, most Product Managers I know would do extensive testing of the product, primarily of new features or features that were modified; and also spent time in the beta programs, discussing with the beta users about specific features or providing clarification or passing on the more severe defects.
The usability expert does not play that extensive a role throughout the cycle, but in the initial phases of the cycle, the inputs of the usability expert are critical. I remember a particular cycle in which we were doing a comprehensive redesign of the product, based on a summary of user issues and requests over the past few versions, and also because the product UI looked dates and needed to be modified to seem better and fresher (and those are somewhat nebulous concepts, but you would not believe how well these concepts sound when you pitch the idea to senior management). In such a case, the flow of ideas between the product manager and the usability expert was something that started way before the requirements phase; in fact these could start before the previous version was done and out of the gate.
The usability expert and the product manager have a set of inputs that help them as they start their process, and for larger products, the number of screens that they have could be considerable, so they do need to prioritize. These inputs would be -
- Complaints and suggestions by customers and on the user forums (especially if these get mentioned a lot),
- Inputs from the usability expert and the product manager themselves (if you show product screens to a usability expert, you can be sure that they will have their opinions on the workflow plus and minuses of certain screens, and the product manager typically has a list of peeves about some screens in the product),
- Technical changes that require a modification to an existing screen or make an improvement possible. It is possible that the components used for screen design have gone through certain changes, which in turn ensures that the screen needs modification or maybe there was a certain workflow that was desired but was not technologically possible, but is possible now
- And there could be some other inputs that also lead to screen or UI modifications
The process is somewhat cyclical, with the expert typically laying down a new desired workflow, which would be commented on by the Product manager and sometimes by the product team, and based on these discussions, a new iteration would be made. Because this may need to be done over many UI screens or workflows, the creative mind of a usability expert may do this screen by screen, rather than working over several screens at the same time, thus ensuring that different product teams can get started. This is where the Product Manager can prod and work with the usability expert, atleast being able to detail out preliminary requirements that can be fully detailed out by the usability expert. It can be a challenge for the Project Manager to handle this kind of scheduling, but cooperation with the Product Manager can help make this smoother.