Workers in lower-hour industries—defined by the chartbook as “those in which part-time work is more prevalent, such as retail trade; arts, entertainment, and recreation; and hospitality and food service”—are not only less likely to receive health insurance and paid time off but also, “notably, access to employer-sponsored retirement plans.”

And that makes a big difference. While the chartbook said that more than a third of full-time American workers lack access to 401(k) or 403(b) plans, among workers in lower-hour industries the participation rate is fewer than 3 out of 10, due to lack of access and barriers to taking advantage of whatever plan they might be offered.

Eligibility rules keep them out, many report, and the problem isn’t only that of part-time workers. Full-time workers in lower-hour industries also have significantly lower access rates than their counterparts in higher-hour industries (39 and 29 percent, respectively).

And their account balances are lower, too, “possibly because of plan eligibility rules and less disposable income.” Even when workers have access, they have lower participation rates—another threat to a decent retirement savings balance.

Part-timers, by the way, whether in lower-hour or higher-hour industries, have nearly identical rates of access.

And about those lower balances: “Among all workers,” the chartbook said, “those in higher-hour industries have median account balances that are more than $5,000 greater than the median for lower-hour industry workers.”