In his well-known article, Good Product Manager/Bad Product Manager, Ben Horowitz wrote: “Good product managers take full responsibility and measure themselves in terms of the success of the product”. That includes, of course, making sure that the product owner role is performed as required – the detailed user stories reflect the product manager feature definitions, the prioritization is aligned with the product goals, etc.
While the product owner’s duties can be performed by the product manager, it is not mandatory. When one person performs both roles, it may result in focusing on urgent matters on the account of delving into long-term, strategic activities. A product manager working closely with a product owner (rather than filling this role on their own) can focus on the big picture, without the risk of neglecting the detailed work with R&D – this work is handled by the product owner, supervised by the product manager.
One challenge that arises when the product owner is NOT the product manager is that one of the product owner roles is to represent the voice of the customer to the technical team. If product owners get market inputs only from the product manager and do not have direct access to the market, their ability to represent the customer’s view to the R&D team is limited. This should be solved by involving product owners in customer meetings and other opportunities for direct access to the market. In such case it is important that the product owner’s understanding of the customers is in sync with that of the product manager, so that the message from the market to the organization is coherent.
When working this way, the product team’s interfaces with the rest of the organization are clear – the product owner is the principal point of contact for the R&D team, and the product manager is the principal point of contact for the marketing team, sales team, etc. There should be a well-defined working procedure between the product manager and the product owner to ensure that the product owner’s translation of requirements to user stories aligns with the product manager’s understanding of the requirements, and that they share the same, up-do-date understanding of the market.
A product owner can be of great help to the product manager, as long as the product manager maintains an end-to-end responsibility over the product, including the work done by the product owner. If a product manager thinks her responsibility ends when the product definition is delivered to the product owner for execution, she does not understand her role as a product manager and cripples her ability to build a successful product. Taking control over the two roles, even if one is performed by a different person, is a key element in the success of the product.