We try to capture everything – we really do. But the reality is so much of our wisdom is in our heads and it’s never more apparent than when trying to train someone new.

At FirstRain we have a new executive – the fabulous Daniela Barbosa who just joined us from Dow Jones. She’s smart and experienced and I want to bring her up to speed as fast as possible but pointing her to our systems is, I know, simply insufficient. We think we capture everything about our users and workflow in our salesforce CRM system. We think we capture our contracts in Netsuite and our central wiki. But of course so much of the deep knowledge is tribal – to quote Wikipedia “Tribal knowledge is any unwritten information that is known within a tribe but often unknown outside of it.”

The reality is that the really interesting stuff about your customers, your technology, why people truly buy is in people’s heads. Our customer facing technical team knows the customer’s workflow, the nuances of why they want one choice over another, what internal projects – and opposition – they are facing and need our system to help them solve. It’s impossible to write it all down, and so it’s crucial to share as much verbally as possible.

And it’s one of the reasons that turnover can be so damaging to companies.

Sometimes turnover is good. If you want to change the culture of a company you typically will have to change 50% of the leadership — or more as when Cadence fired it’s entire executive team. If you want to dramatically change your strategy and go-to-market you have to change your business team — as Dell is now bravely doing.

But short of dramatic change, turnover is expensive simply because you lose and have to re-learn so much tribal knowledge. Especially with your R&D team and with customer support. The R&D team knows where the bodies are buried in the code; the customer support team knows the truth about customer use and where they find value.

It is, of course, important to document the knowledge you have, but when you are growing and moving fast it is also important to value, and protect tribal knowledge and bring your team together frequently and efficiently to talk through and share what’s in people’s heads.