Clients often ask us why we don't do talent assessment. We do organizational design, and the two seem like they belong together. In a restructuring, you first redesign the organization, then assess who should fill the new roles. Why not have one firm do both? It would be simpler, and it might even be cheaper.
The answer is that the two jobs work against each other. Not a little, either. Enough that doing both usually makes each one worse.
Start with how org design actually works. You can't figure out a company's real structure from its org chart. You have to talk to people, lots of them. You need them to tell you where decisions get stuck, which teams duplicate each other, and which managers are actually running things versus nominally in charge. The useful information is almost always the stuff people would rather not say out loud.
Now imagine you're one of those people, and you know the firm interviewing you will also decide whether you keep your job. What do you say? Whatever makes you look good. You don't mention that your team could be folded into another one. You don't admit that half of what you do isn't really necessary. You'd be foolish to.
So the moment a firm does both, the interviews stop being interviews. They become auditions. And you can't design a good organization from auditions.
The second problem is subtler, and in some ways worse. It's about the designer, not the people being designed.
The right way to design an organization is to start from what the business needs to do and work backward to the structure that does it best. The people come later. But if you've already been assessing the people, you can't unknow what you've learned. Without quite noticing, you'll find yourself drawing boxes around the people you rated highly and designing out the ones you didn't. The structure ends up shaped like your opinion of the current team rather than like the strategy.
What makes this kind of bias dangerous is that it actually just feels like judgement, not bias. A consultant who has spent two weeks with an impressive VP of operations will naturally find reasons why operations should report straight to the CEO. Maybe it should. But you can no longer tell whether that's the right answer or just the comfortable one.
There's also a more obvious conflict of interest, though we think it matters less than the other two. A firm that sells both services has a reason to design organizations that need a lot of assessing.
None of this means talent and leadership assessment don't matter. They do. Putting the right people in the right roles is half the battle. It's just a different battle, and it goes better when it's fought by someone else.
So when clients ask why we don't do both, the honest answer is that we'd be worse at the thing they hired us for. We'd rather do one job well and hand off cleanly than do two jobs in a way that quietly undermines both.