But not all industry experts are convinced that managed accounts are the be-all and end-all of retirement preparedness; a Cerulli analysis in May warned that, while managed accounts have their place for some 401(k) investors, no one should expect them to outpace target-date funds as the primary qualified default investment alternative in defined contribution plans.

Still, it’s evident from Fidelity’s latest study that if people understand managed accounts, they seem to like them — and if they don’t understand them, they don’t use them.

Among participants enrolled in managed accounts, the study found, 48 percent said that the ongoing monitoring of their investments was one of the most valuable things about the offering. In fact, 44 percent said that annual review was essential.

In addition, 38 percent said that ongoing management was beneficial, too.

When it came to employees who don’t use managed accounts, the study found that 39 percent said they don’t use them because they don’t understand them — and 25 percent cited that lack of understanding as a major barrier to using them.

Once it’s explained to them what a managed account is, and how it offers ongoing professional management of their retirement accounts, Fidelity said, 54 percent said such an account would be relevant to their needs and 52 percent said they’d find the service useful.

But if employers choose to adopt managed accounts, Fidelity said, they should also adopt best practices for employee education. It said that 80 percent of Fidelity clients who adopt workplace managed accounts are using employee education programs.