What Does It Mean to Say That Investing in a 401(k) Is Safer Than Investing in Stocks?

The NYT reported the results of a telephone survey which found the 41 percent of respondents thought a 401(k) or IRA was a better long-term investment vehicle than investing in stock. It's not clear what question people thought they were answering. The vast majority of people who invest in stock do it through a retirement account. Therefore, it's not clear what it would mean to say that investing in a 401(k) or IRA is better than investing in stock.