Keeping employees engaged in the midst of layoffs, pay cuts and a skittish economy can be difficult. A new study suggests that organizations should adopt policies that address different generations of workers' needs, rather than attempting one-size-fits-all fixes.

The study, conducted jointly by Boston College's Sloan Center for Aging and Work and MetLife, examines what engages employees according a number of factors—especially age.

The results show different generations of workers want different things from their jobs, requiring a variety of strategies to engage everyone and boost productivity. For example, Millennials (those under 30) want flexibility, while older Gen Xers (ages 38 to 44) are most engaged in managerial roles with job security.

"Given the downturn, employers are very interested in doing the most they can with the workers continuing with them, and these are low-cost ways of enhancing employee engagement," said Christina Matz-Costa, a research associate at the Sloan Center and one of the study's authors.

However, there were some desires that appealed to all age groups such as flexibility; workers want more control over where, when, and how they work.

Matz-Costa says employers shouldn't necessarily tailor their policies to these specific factors. But in trying to motivate workers, they should consider how life and career stage affect employees' work experiences.

The study also found that older workers tend to be the most engaged, refuting the idea that employees close to retirement becoming less committed.

"It counteracts the stereotype that as workers get older they're disengaging as they transition to retirement," said Matz-Costa.