The Part of FP&A Nobody Actually Teaches You

Here's something I keep noticing after sitting inside hundreds of finance implementations.

The model is rarely the problem.

I had Paul Barnhurst on Making Cents with Charlie a few weeks ago. Founder of The FP&A Guy, host of three podcasts, 12 years inside finance teams at places like American Express and DigiCert. The kind of person who has seen enough finance functions to spot patterns the rest of us miss.

And he said something I genuinely could not shake after we stopped recording.

He said the P in FP&A stands for planning. But most finance teams spend the majority of their time on the A. Building the model. Cleaning the model. Maintaining the model. And somewhere along the way, the actual thinking, the assumptions, the strategy, the business context that makes the model mean something, gets maybe 20% of the week.

His grad school professor used to grade students almost as much on their thought process as on the model itself. Did they understand the industry? Did they interrogate the drivers? Could they defend the assumptions in the room? In his view, the math was almost secondary. Get the thinking right and the numbers follow.

I have seen this play out over and over again in client work. The analyst with the cleanest model and the weakest assumptions. The CFO who trusts a forecast not because the formulas are airtight but because someone actually thought through what was behind them.

Paul put it simply: all models are wrong. Some are useful. The question is just how wrong you are willing to be.

That reframe is worth sitting with. Because it shifts where the pressure belongs. Not on whether the model is perfectly built. On whether the assumptions are honestly challenged, properly documented, and actually connected to how the business operates.

And if you have been using AI to do more of the modeling work, which most of us are now, this matters even more. What AI cannot replace is the judgment to know when the output is wrong. That judgment only comes from doing the uncomfortable work of understanding the business before you ever open a spreadsheet.

One question worth sitting with this week: when did you last spend more time questioning your assumptions than building around them?

The full conversation with Paul is on Making Cents with Charlie.

Read the full episode recap