Summarized in a WSJ article at https://www.wsj.com/business/entrepreneurship/startup-lose-early-employee-6de8bbd3 https://www.wsj.com/business/entrepreneurship/

Summarized in a WSJ article at https://www.wsj.com/business/entrepreneurship/startup-lose-early-employee-6de8bbd3 https://www.wsj.com/business/entrepreneurship/startup-lose-e... archived at https://archive.ph/ksjlg https://archive.ph/ksjlg with title and subtitle "When Startups Lose a Very Early Employee, They May Never Recover. A study also found that when an employee hired in the startup’s second year leaves, the impact is minimal"