How executive references are actually taken

There are two reference processes, not one

The formal one uses the names you gave, happens late, and is largely confirmatory. The informal one starts much earlier: somebody on the hiring side knows somebody who worked with you, and asks them what you are like. That conversation is unstructured, unrecorded and often decisive.

This is not a scandal, and it is not going to stop. It is what senior networks are for, and it is the same mechanism that gets you considered in the first place. It simply means your reputation is being consulted before you are asked who to consult.

What this changes about how you behave

• Assume anyone you have worked with may be asked. That includes people two levels below you, whose view of how you treat a team is exactly what a board wants to know.
• Leave well, every time. A difficult exit handled gracefully is survivable; one handled badly follows you through a small market.
• Keep relationships warm with people who would speak well of you, before you need them to. A reference from someone you last spoke to four years ago is worth less than one from someone you had coffee with in June.
• Do not try to control it. Attempts to police what former colleagues say are always visible and always counterproductive.

The reference you cannot choose is the one that decides it. That is an argument for how you behave on the way out, not for how you brief the three names on the form.

Preparing the formal ones properly

The honest limit

You cannot audit what is said about you, and a search that is going to be decided by an informal conversation will be decided by it whatever you do. What you can influence is how many people would take that call and speak warmly, and that is built over years rather than in the fortnight before an offer.