The pain experienced by the "set it and forget it" faction of Americans saving for retirement got a hearing in the nation's capital last week as regulators, mutual fund industry representatives, employers, consultants and others took up the issue of what to do about target date funds.

The funds automatically move more of an investor's retirement savings from stocks to bonds as the investor nears retirement. They became a more popular retirement savings option in 2007 after the U.S. Department of Labor told employers that target date funds were one of several suitable options for employees who did not select how to invest their 401(k) money.

Nearly 70 percent of the retirement plans administered by Vanguard offered target date funds as an option last year, up from 13 percent in 2004. Vanguard's Center for Retirement Research found that 37 percent of the 3.2 million employees saving through those plans used target date funds, up from 11 percent in 2004.

If they are nothing else, retirement savers are couch potatoes when it comes to changing the way their 401(k) money is invested or regularly rebalancing their portfolios as financial planners recommend.

Target date funds do those jobs for them. The funds held assets of $176 billion as of the end of April, according to the Investment Company Group, which represents the mutual fund industry.

But last year's stock market collapse called the "set it and forget it" strategy into question.

Investors who had their retirement savings in 31 target date funds designed for workers planning to retire in 2010 lost an average of 25 percent last year, according to Securities and Exchange Commission Chairman Mary L. Schapiro. She said the losses ranged from 3.6 percent to 41 percent.

"These varying results should cause all of us to pause and consider whether regulatory changes, industry reforms or other revisions are needed," Ms. Schapiro said in a statement prepared for an SEC-sponsored meeting held Thursday.

One of the speakers at the session, Vanguard's John Ameriks, said the disparity of results had more to do with what kinds of stocks and bonds target date funds held than with the percentage of stocks and bonds in their portfolios.

Funds that held more U.S. stocks did better than funds that had larger positions in stocks of companies in developed or emerging markets, said Mr. Ameriks, who heads the investment firm's Investment Counseling & Research Group. On the bond side, funds with more exposure to U.S. government bonds did better than funds that held more corporate bonds or mortgage-backed securities, he said.

A key component of target date funds is the "glide path," industry parlance for how managers of the funds transition them from more risky investments to more conservative ones as investors age.

"We believe that failure to adapt to the changing nature of investment risk can turn a glide path into a glide trap because the historical asset class return patterns on which it is based will inevitably fail in periods like we have seen over the past year," Jeffrey S. Coons of Manning & Napier Advisors wrote in a letter to the SEC.

Critics point out other problems with target date funds, including fees. Many target date fund sponsors build their portfolios using other mutual funds they offer. In many cases, investors pay the fees those funds charge as well as a "wrapper" fee by the target date fund.

Others chide mutual fund operators for trying to capitalize on the growing market for target date funds by boosting returns to lure investors.

"The truth is that the target date industry entered in a performance race in 2006 and 2007, raising equity allocations," said Ron Surz of Target Date Analytics, a firm that measures the performance of target date funds.

Then there's an issue finding the fund designed for a particular year. Target date funds typically are offered in five-year increments: for those who want to retire in 2010, 2015, 2020 and so on. There isn't one designed for someone aiming to retire in July 2017. More importantly, are you as certain about your retirement date as you were last Father's Day?

Finally, many advisers say that while target date funds are fine for young investors just starting out, they become more problematic as workers age and their finances become more complicated.

There's no doubt target date funds have encouraged more workers to begin saving for retirement. That's a good thing given that fewer workers are covered by traditional pension plans and concerns about the future of Social Security remain.

However, the shortcomings of the funds must be addressed, not only by the SEC and the industry, but by investors as well. After everything we've been through over the last nine months, anyone who believes that "set it and forget it" makes personal responsibility unnecessary is seriously delusional.