A Medical Affairs colleague once said, “How many plumbers do we really need to fix one problem?”

I laughed. I thought about it again this week after being tagged in more Medical-versus-Commercial discussions than I could keep up with.

Over the past several weeks, I've written about Medical and Commercial mapping the same medical experts, medical education sitting within Commercial, and what happens when Commercial becomes increasingly clinically sophisticated. I've also explored the disconnect between clinical understanding, patient access, and ownership of the patient journey.

Different discussions, but they keep coming back to how we define Medical Affairs: its purpose, capabilities, boundaries, and reporting lines. These questions are important, and so are the scientific independence and appropriate governance.

But here's what I've been thinking as these conversations continue. We spend so much time debating who owns the work. How often do we question whether the work we're doing is still what the market needs?

And when the market tells us our original assumptions were wrong, are we willing, and more importantly, able to change the plan?

Maybe the plumber question was never about how many people show up. It's about what each of them thinks the problem is.

Picture a product with slower-than-expected uptake. Medical, Commercial, and Access are looking at the same market, but each brings a different perspective.

Illustrative examples. Actual responsibilities and responses vary by organization.

Any of these interpretations may be correct. But each can also be incomplete.

Consider a third-line therapy where treatment sequencing is guided by clinical guidelines. Medical Affairs may be doing an excellent job closing knowledge gaps. But what if physicians already understand the evidence, and the forecast simply assumed more patients would reach third line than actually do? More engagement won’t change that.

Or perhaps the barrier is more practical. The community practice can't administer the treatment, or the referral pathway isn't working.

What if the product isn't underperforming because our teams aren't doing enough, but because our assumptions about the opportunity were wrong?

Someone in the organization may already have identified the problem. That doesn't mean the observation has changed the organization's response.

Each function can execute its plan well while the underlying constraint remains.

When performance lags, I've seen organizations respond by increasing the activities they're already tracking.

More calls. More scientific interactions. More programs. It looks like accountability. Every dashboard shows effort increasing.

But we may be investing more heavily in a response before confirming that we're solving the right problem. And the busier everyone looks, the harder it becomes to question the diagnosis.

I don't think this necessarily happens because people are protecting their turf. When functions are evaluated against their own plans, they're naturally encouraged to demonstrate progress within those plans, even when new information suggests the market needs something different.

Years ago, on a dermatology team, we wanted dermatologists to recognize psoriatic arthritis (PsA) earlier in their psoriasis patients. We assumed dermatologists needed more education about PsA. So that's what we did.

But the feedback from our MSLs told a different story. Dermatologists were polite. They'd listen, nod, and move on. The discussions were often short. PsA wasn't something many considered their responsibility. That was rheumatology's territory.

We could keep educating them, but we had to ask whether more disease information would actually change anything.

So we decided to try something different. It took about a year to get the program off the ground. We needed dermatology and rheumatology experts in the same room, along with patients, and we didn’t have that expertise in-house. Nothing in the original plan had made room for bringing it in.

Instead of another presentation about PsA, we focused on what happened after a patient was referred. How long did it actually take to see a rheumatologist? What could happen during that delay? We also made practical PsA screening tools easier for dermatologists to access and use.

Afterward, our MSL insights showed dermatologists raising PsA more frequently. That didn't establish whether referrals happened sooner, but it suggested the conversation was changing.

The scientific information hadn't suddenly become more compelling. We had changed its relevance to the dermatologist's practice.

We thought the problem was insufficient education. The field was telling us that dermatologists didn't see why they needed to act.

Notice how long that took. The insight was there early. Changing the response was the hard part.

This brings me back to Sunday's discussion about what actually changes because of Medical Affairs' work.

Medical brings a scientific and clinical perspective that other functions may not have. Commercial and Access encounter other parts of the same market.

No single function has the complete picture. Yet we spend considerable time discussing the quality and quantity of MSL insights. How consistently do we examine whether those insights challenge our understanding of the market?

When the field repeatedly tells us an approach isn't working, do we reconsider the approach, or ask the field to execute it harder? And who has the authority to make that decision?

For people in the field, that's the difference between being asked to generate another interaction and being equipped to address the need in front of them.

I'm not suggesting every function should be measured against the same outcome.

Hold everyone accountable for brand sales, and Medical's scientific independence becomes a concern. Hold everyone accountable for engagement, and we're back to counting activity.

What I'd rather see is leadership periodically revisiting the assumptions behind the strategy:

Medical brings scientific and clinical insights. Access contributes observations about reimbursement and treatment pathways. Commercial contributes its understanding of market behavior.

Each function retains its responsibilities and governance. But leadership needs to examine whether those perspectives change the overall interpretation of the market.

And sometimes, that learning should change the plan, including where resources are deployed.

A diagnosis that made sense before launch may no longer explain the market two years later.

Scientific questions evolve. Treatment pathways change. New evidence and competitors emerge. Yet the field model, engagement expectations, and performance measures can remain largely unchanged even as the brand plan evolves.

Product maturity doesn't automatically mean less Medical Affairs. It means the work Medical Affairs needs to do may have changed.

Maybe the problem was never the number of plumbers. It's that everyone arrived with their own tools, and each saw the problem their tools could fix.

The question isn't whether Medical, Commercial, and Access are executing their plans. It's whether those plans still reflect the problem the market is presenting.

What evidence would make your organization change the plan, rather than simply increase the activity?

Pick one assumption your brand or field plan is built on. Then ask your MSLs one question: What are you hearing that contradicts it?

If the answer surprises you, that’s your diagnosis conversation.

Reply with the assumption. I’ll tell you how I’d test it.

P.S. Next week: Medical Information. We assumed AI would automate it. What if we underestimated what it was telling us?