How do these roles typically vary in an organization that has both?
In GENERAL the difference is that Business Analysts work for enterprises that consume technology, and Product Managers work for vendors who provide technology to enterprises, smaller companies and consumers.
In most legacy enterprise environments things are organized around projects and not products (at least products implemented in software). Business Analysts are generally responsible for making sure that the requirements of the business are considered in the project at hand.
In a software company on the other hand the software is not a "project" but rather the reason that the company exists at all. There is not a project for each release, but rather and ongoing stream of releases managed by a Product Manager, who is the CEO of the product.
Now this is changing due to digitization. Due to digitization, more enterprises are becoming "software defined" and rely upon software to compete online. So their online initiatives become products instead of projects. This will inevitably lead to enterprises who have digital initiatives to need to organize as software companies and to replace project managers and business analysts with product managers.
So as digitization proceeds, business analysts and project managers (at least the good ones) will (and should) become product managers and these distinctions will disappear.
I've found that the titles are interchangeable in a lot of resources and written material, but there is a distinct difference. I think Business Analyst is a role that can be taken on by a PM just as the role of a Product Owner can be taken on by a PM. In large companies a single person would take on a single role, but in smaller companies one person can handle the roles of Product Owner, a Business Analyst and a Product Manager.
A Business Analyst specifically deals with business processes, the business model and how that translates into business strategy and the detailed business and technical requirements. While a PM can preform all the listed tasks, they also focus on the long term strategy and vision as it relates to a specific product or products that a business offers.
I agree with most of what Maria said, but suggest that BA's don't get to the strategy level - at least not in my experience. They would hopefully be aware of the strategy, but tend to operate at the process level and translating that into technical requirements.
Product Managers work more at the product strategy level, develop a comprehensive product plan, sense market needs, prove out concepts with the market and set priorities. Where the organization is not big enough to isolate those roles (most companies?), Product Managers take on the analysis role as part of their work.
In organizations that isolate the roles, the Product Manager might sense a need (be it internal or external) and have the BA understand it in more detail and propose a solution. Then the Product Manager may guide a PoC (working with the BA) or an early MVP to prove out the need or adjust the solution (or cancel the project). If the feature moves forward, the Product Manager would be responsible for figuring out how the new solution fits into the product vision, roadmap and schedules. The BA would be called upon to flesh out details and translate business needs into specific detailed requirements.
My experience and observations is that the two roles are fairly similar in most cases with two distinct differences. The big differences I see:
- Product managers tend to work directly on products that an organization sells or at least offers to people outside the organization. Business Analysts tend to work on "internal" products, ie solutions that are intended for use by those inside the organization.
- Product managers tend to be explicitly expected to make decisions. Business analysts tend not to explicitly make decisions but certainly play (at least they should play) a role in making sure decisions are made.
Those are generalizations and there are certainly exceptions so it depends on the context you look at. I would say that product management is a more appropriate step in the career ladder for BA's that project management.
All that said, both BA's and Product Managers are product people.