tl;dr:
"Call center employees who volunteered to WFH were randomly assigned to work from home or in the office for 9 months. Home working led to a 13% performance increase, of which about 9% was from working more minutes per shift (fewer breaks and sick-days) and 4% from more calls per minute (attributed to a quieter working environment).
Home workers also reported improved work satisfaction and experienced less turnover, but their promotion rate conditional on performance fell. "
Pay attention to the last sentence.