The three services sound similar from the outside. Here's the one-question test that tells them apart.
"We need help with X" can mean three very different kinds of engagement. Getting the category right up front saves a lot of wasted conversation.
Ask: is this ongoing, time-bound, or a one-time problem to be solved?
Real situations don't always sort cleanly. A consulting engagement often recommends outsourcing a function — which then becomes a BPO relationship. A stalled project sometimes turns out to be stalled because of a deeper process problem, which starts to look like consulting. That overlap isn't a flaw in the framework, it's normal — the point of the question isn't to file the problem in exactly one box forever, it's to know what to ask for first.
"Our invoicing takes too many internal hours every month" — ongoing, no end date — BPO. "We're launching a new product line by Q2 and need someone to own the rollout" — time-bound, defined finish — project management. "Our operating costs are too high and we don't know why" — a specific problem needing a diagnosis and a fix — consulting.
That's normal, and it's a fine way to start the conversation — describe the situation, not the service category, and let the categorization happen from there. It's usually faster to talk it through than to guess correctly in advance.
Tell us what you're dealing with — we'll tell you exactly how we'd approach it.