Here is the outcome nobody models.
The partner arrives. The clients follow, more or less as promised. The billings land. On every metric the firm tracks, the hire has worked. The business case is vindicated, the sponsoring partner is quietly pleased, and the whole thing is cited internally as evidence that the strategy is sound.
Two years later the partner leaves.
This is not a failed hire in the usual sense. Nothing went wrong with the book. What went wrong is that the partner never became part of the firm, and a partner who has delivered their clients but not built a life inside the place has no particular reason to stay. They have their relationships. They have their revenue. What they do not have is any of the invisible things that make leaving costly.
There is an uncomfortable logic to it. Delivering the book is precisely the achievement that makes a partner more attractive to the next bidder, because they have now proved the thing every firm is anxious about. Portability, once demonstrated, becomes a permanent asset on the open market. The successful lateral is, by definition, the most saleable lateral.
So the firm has spent a great deal of money running a two year advertisement for a competitor.
The word for what is missing is belonging, and it is doing more work than it appears to. Belonging is not sentiment. It is the accumulated cost of leaving: the colleagues who would be let down, the initiatives half finished, the standing that took three years to build and does not travel. A partner who has that is expensive to poach. A partner who has only their own clients and a desk is not expensive to poach at all.
Heidi Gardner’s research at Harvard Law School points the same way from a different direction. Laterals who genuinely collaborate with their new colleagues are significantly more likely to stay longer, to hit or exceed their targets, and to thrive. Collaboration is not a nice-to-have layered on top of the revenue. It is the thing that makes the revenue durable.
Which suggests firms are measuring the wrong thing at exactly the wrong moment. The billings tell you about the last twelve months. The network tells you about the next five. The revenue number arrives early and reassures everybody, and by the time the retention problem becomes visible, the partner has already had the conversation.
BTI’s formulation is the one to end on. Get it right and you get the clients and a happy lateral. Get it wrong and you have simply paved the exit ramp.
Sources: Heidi K. Gardner and Anusia E. Gillespie, Smart Collaboration for Lateral Hiring, 2018; BTI Consulting, May 2025.
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