More than half of those 50 and older who were not working and not searching for work, the study finds, said that they would work in the future if the right opportunity came along. Older college graduates were even more likely to say so, at 60 percent compared with just 40 percent for older nongraduates. In addition, 39 percent of workers 65 and older who were currently employed had previously retired at some point.

Older job seekers are less likely than younger job seekers to score formal benefits highly in their criteria for going back to work—and that's true whether they are employed and searching for a different job, unemployed and actively searching for work, or not in the labor force but open to the possibility of returning to work if the right opportunity arose.

Such benefits as dental insurance, life insurance, or paid time off are not ranked as essential or very important, while things that mattered more to them are having some control over how they do their work, the ability to set their own pace, and the physical demands of the job.

Respondents to the American Working Conditions Survey also say that they want meaningful work—and more than two-thirds of older workers reported that they felt satisfaction over work well done and felt that they were doing useful work.

While there was no real difference between older men and women on this, it was a different story for prime-age workers. About two-thirds of prime-age women also reported having fulfilling work, but just 54 percent of prime-age men said the same.

Another interesting finding is that older workers, in particular older male workers lacking college degrees, are more likely than prime-age workers to say that they apply their own ideas (87 percent versus 83 percent in prime age).

They are also more likely to say they solve unforeseen problems (85 percent versus 78 percent) in their work, and less likely to say that they perform monotonous tasks (54 percent versus 64 percent of prime-age workers).

The study theorizes that one explanation for the difference is that older Americans have worked their way into more interesting jobs over their careers. Another is that "Americans working tedious, unfulfilling jobs simply left the workforce earlier than those with fulfilling jobs."

However, one area older workers say jobs fall short is in providing "constructive relationships."

Older workers are less likely, by 5 to 6 percentage points, than younger workers to say that their boss is supportive, cooperation with colleagues is good, and conflicts are resolved fairly.

Older workers also say there's less opportunity for career advancement than prime-age workers do (27 percent versus 40 percent), although at least in part this could be due to them already having advanced further in their careers than their younger counterparts.

Working conditions, the study finds, could play a major part in keeping those close to retirement actively in the workforce, and in wooing retired workers back to the job.

The AWCS suggests that keeping older Americans engaged by giving them control over when and how they do their work, accommodating their changing physical capacities and improving their connection with coworkers may be appropriate places to start.