According to the 2013 Retirement Confidence Survey by the Employee Benefits Research Institute, 49% of American workers are not too confident or not at all confident that they will have enough money to live comfortably throughout their retirement years. Sure, the current state of the economy has a lot to do with that, as well as people not saving enough. And, of course, younger people tend to be less confident about Social Security.

But I think a good chunk of the lack of confidence is actually a lack of understanding about how much it will take to live comfortably. Saving for retirement is not like saving for anything else. If you are saving for a new car, you know precisely when you have enough money to buy that car. How do you know when you have enough money for retirement?

There are so many unknowns after retirement. And the main one is that people don t know how long they are going to live. A big fear of retirees is outliving their assets, otherwise known as longevity risk. But there are some retirees who are more confident that they won t outlive their assets: retirees with defined benefit (DB) pension plans.

A pension plan pays a benefit amount every month until a person dies. That can t be outlived. The monthly amount is typically based on the number of years of service with an employer and may be tied to salary. If the person is married, the benefit can continue to a spouse after death.

Problem is, though, that these types of plans are becoming less and less prevalent every year, as companies are freezing and/or terminating them. So even if the economy gets back on track and people can start saving more, it's not clear we ll see an improvement to the confidence level of American workers as to whether or not they will have enough money to live comfortably throughout their retirement years.

I recall a series of commercials a few years ago that showed people walking around with six or seven digit numbers, looking confident, as if that were the precise number they needed to retire. How much more confident would they have been walking around with their defined benefit pension plans?