Olivia Mitchell (U Penn) looks at opt-out version of 401(k) in Bloomberg BusinessWeek
"How Opt Out Keeps People In" - Bloomberg Businessweek. 8/23/2012.
Olivia Mitchell says that the 401(k) retirement plans with automatic enrollment plans that require opt-outs to dis-enroll are catching on in many companies. They tend to have many more participants than opt-in plans.