What exactly is a product manager?
Not "CEO of Product"
Textbooks typically define a Product Manager as the “CEO of a Product”, at a high level this is sort of correct but it sets an incorrect expectation from the role. If taken too literally, it will actually set you up for failure rather than success. Why I think this definition no longer works is quite simple. Let's first look at what's expected of a CEO at a high level.
A CEO owns the company strategy and focuses primarily on creating shareholder value through ensuring execution of that strategy. Now you may be thinking: “hold on, I’m told that a PM owns Product strategy and execution”. It is incorrect to think that most PMs actually own Product Strategy, in fact I’ve met very few Product Managers who truly own Product Strategy for even a small product.
This may be true in limited and very senior PM roles with a tall and established Product organisation hierarchy, but generally Product Strategy is owned by the executive branch of Product, i.e. the Head / Director / VP of Product or the Chief Product Officer. What most PMs actually own is usually the feature roadmap that is ultimately pegged to the Product Strategy.
The next important bit is “creating shareholder value” and if you distill this down to a PMs role, the reality is that most PMs may not end up working on Products or features that actually contribute to the company’s top line. Ultimately the best PMs will go on to own Product Strategy and will build products that contribute to the company’s top line however it is naive to imagine you will start off a PM role... doing that.
Value Contributors & Outcome Drivers
I prefer to consider PMs as "value contributors" and "outcome drivers" focused on part of, or all of a product that a company sells. They do this by ensuring that ensuring engineers, designers, data scientists and other stakeholders are focused on the right problem to solve, and communicate the value of solving that problem effectively.
As product managers don't manage anyone directly, they do this through influence based on rationale and ensuring everyone can connect the dots between product strategy and company strategy. A product manager therefore is a leader, and leaders have to ensure people are driving towards the best outcome.
Jack of all trades
As someone who gets things done by way of influence, product managers need to have a broad skillset. They need to understand enough about engineering, design, marketing, etc to ensure that the output delivered can actually deliver the expected outcome. While generally teams should be trusted to deliver the best outcome; a product manager is expected to and should weigh in on the quality of output. And once again this is done by means of influencing and explaining why the output will or won't meet the desired outcome. This is when a product manager truly has to think like a CEO and ask the question... "is this the right thing for this business?".
None of this is possible without understanding customers and what keeps them up at night. A product manager is expected to know what their customer looks like, i.e. everything from why they use the product, how they got to know about the product, why this product vs any other and what they're willing to pay for the product (yes willing to pay, not what they pay currently). To be an effective product manager, one must talk to customers all the time and have a constant feedback loop.
Everyone has tried defining what a product manager is, but reality is, the world has not settled on one definition because the role is still in its infancy when compared to other roles like engineers for instance. Lastly, if you were hoping for diagrams, there's an overabundence of venn diagrams out there, but this one is the classic by Martin Eriksson, which gets it right: