Why many Americans can't save for retirement

Poor people would save more money if they could.

So concludes a new study that found that only 12 percent of low-income older Americans put money in a 401(k) or other retirement plan. The research, from Boston College's Center for Retirement Research, looked at people who were between 50 and 58 years old and had household incomes of three times the poverty line. In 2010 that was less than $36,357 for one person and less than $46,800 for two people.

The chief differences between the low-income workers who participate in a retirement plan and those who don't are education and the size of the company they work for. Of those who are saving for retirement, 17.4 percent hadn't graduated high school, 16 percent had graduated from college and 76 percent work for large companies. Among those who don't participate, 34 percent hadn't graduated from college, 8 percent had graduated from college and 43 percent work for large companies, while 40 percent worked for small companies.

Currently, about half of U.S. private sector workers don't participate in a retirement plan and most of them have lower incomes. The low participation rate is a growing concern because of the widespread shortfall in private savings in the U.S. and modest Social Security benefits for most retirees.

As the report notes, "A failure to sign up can't be blamed for the dismal savings rate of this low-income group. Instead, the problem is that many never get the chance."

There are four major reasons poor people approaching retirement struggle to save, according to the researchers:

• Lack of employment: Only 42 percent of low-income older people are employed at any given time.

• Lack of access: When they are employed, 66 percent work for employers that don't offer a retirement savings plan.
  
• Lack of eligibility: Many low-income people work several part-time jobs, and many employers offer a retirement plan only to full-time employees.
  
• Lack of knowledge: Many workers don't know they have to enroll in a retirement plan.

The study's authors suggest the best solution would be to require employers to offer a retirement savings plan to workers who aren't covered and then automatically enroll them. Yet even this best-case scenario would raise low-income participation to only 42 percent.

The study is just the latest of many to cast doubt on the effectiveness of the system of 401(k), IRA and other accounts for most workers. According to the Federal Reserve roughly half of all U.S. families have no money set aside for retirement.

According to the Employee Benefit Research Institute, only 18 percent of U.S. workers say they are "very confident" of having enough money to live comfortably during their retirement years. (For more information, see CBS News' special report, Eye on America: Retirement, which explores the changing nature of retirement and how to prepare for the future.)

A report last year by the Economic Policy Institute found that the retirement system largely benefits higher income workers the most because they can actually contribute enough to make 401(k) plans work for retirement.

"Retirement-income inequality has grown in part because most 401(k) participants are required to contribute to these plans in order to participate, whereas workers are automatically enrolled in defined-benefit pensions and, in the private sector, are not required to contribute to these plans," the liberal-leaning think-tank found. "Thus, higher-income workers are much more likely to participate in defined-contribution plans. In addition, higher-income workers have more disposable income and a higher investment-risk tolerance, receive larger tax breaks, and are more likely to work for employers that provide generous matches."