Product Manager vs. Product Owner
TL;DR: Product manager is a career, product owner is a role on the Scrum team.
In times when code is cheap and time to market has been significantly shortened, the role of product manager has gained in importance. The need to discover new business opportunities often leads to the expansion of product development, with new people being either hired or recruited from other positions. While this is good in general, we too many times end up with a bunch of people without a clear idea of what their tasks and responsibilities are, making things rather rapidly worse.
A common misconception is to have both a product manager (PM) and a product owner (PO). The idea is to split the tasks to create more room for focused work, usually having the PM concentrate on high-level business requirements and the PO on low-level details and technicalities. Sadly, this idea falls short for several reasons: When the product role is divided, nobody really owns the product and feels the ultimate responsibility for it. Moreover, it’s effectively impossible to devise product requirements without knowledge of low-level details, especially UI/UX and engineering, because without those, the product manager doesn’t even know what is possible. Product management must be in a tight exchange with designers, engineers, and marketing to create a proper modern solution to customer problems.
The difference between a PM and a PO is, in fact, categorical: While the former is a career, the product owner is a role that a product manager takes on an agile team. Essentially, a product owner is a set of tasks that product managers tackle as part of their jobs when working in agile development. But those tasks are only an addition to product management, which is the main job. That’s why a product owner, as another person, is often degraded to a mere bureaucrat, an administrative converter from requirements to written stories, who doesn’t actually own anything.
Although people are often unhappy with this situation, they are often unaware of the biggest risk. They usually talk about the inefficiency of communication, meaning that collaboration between PM and PO is expensive and resource-wasting, rather than about the effectiveness of the work, meaning that the purpose is not fulfilled and no great product is created. While the former point is valid, the latter is essential for the survival of the organization.
It’s okay to call the product manager position a product owner, as this sounds more modern and, yeah, agile, as long as the person doing it understands the responsibilities that come with it. In that case, however, the temptation to hire an additional product manager might be harder to avoid because this role is occupied by the product owner rather implicitly.
Bonus: Product manager vs. project manager
A project is temporary work with a clearly defined scope, start and end dates, and a budget, whereas a product is a continuous good or service that generates ongoing value by solving customer problems. Familiar examples of projects include a prototype of a module, a redesign, or a migration of a legacy system.
Projects are a way to carry out a product and should be well managed in order to hit deadlines, stay within budget, keep stakeholders on track, and so on. For such tasks, having a separate project manager position is a valid approach.
It’s not advisable to have a product manager do the project manager’s job because of the conflict in goals (long-term vs. short-term).