According to Personnel Today as much as 22% of employees have changed their minds after accepting a job due to problems during the onboarding process. These are people who have made the effort the apply for a job, been interviewed, been offered a role, accepted the role and after all that decided not to start their new job anyway.

There are several things to reflect on if this an issue for your organisation. Onboarding starts the moment a person accepts an offer of employment. If you have spent a lot of money, time and effort attracting people to your organisation, I can think of no logical reason to stop engaging with them just because they've been sent an offer letter. After all, other organisations will keep recruiting, your candidate will keep receiving job alerts and maybe even communication from other employers that they have previously registered with. So no further engagement from you in the weeks or months before they join really is a risky strategy.