When KPIs are shared with other GTM teams (such as product revenue or conversion rates) how do you ensure prove contribution or should you avoid?

This is tricky. It's very important to build alignment across team with shared KPIs at a high level, (including product revenue or conversion rates), while also identifying KPIs that are more directly within Product Marketing control (like pipe generation, or MQLs).

Having these higher altitude shared goals are valuable because they ensure that all teams are taking ownership of getting to the end result, driving collaboration across teams and through all of the steps to get there from Marketing, Sales Enablement, GTM, Sales Operations, etc. If we only focus on direct outcomes for PMM, we risk getting initiatives only partway to where we need to go as a business. I've seen this issue many times where MQLs don't get scored or followed up on, and then don't drive product revenue for example.

I wouldn't necessarily avoid trying to identify contribution when sharing KPIs with other teams, but I'd caution not to get overly aggressive about seeking "credit" for those metrics either. PMM can be challenging because the work we do isn't always a 1:1 input to output of identifiable metrics that quantify our impact.

What I would recommend is having very transparent conversations with key stakeholders and collaborators across the other departments with whom you might be sharing a KPI, let's say contribution to pipeline with demand gen/growth for example.

First ensure that contribution to pipeline is the right shared KPI and use it as a way to build trust and collaboration with DG/growth. In this case, PMM is likely creating the messaging framework and product content that the DG/growth team(s) need in order to execute their campaigns. In this example, the contribution to pipeline would be shared, not split.