Are so-called “single asset allocation plans” a better deal than building your own asset allocation program out of individual funds?

John Hancock certainly thinks so.

In a brand new survey of John Hancock Retirement Plan services plan participants, the investment firm found that respondents “who invested exclusively in a single John Hancock asset allocation portfolio earned better returns on average than participants who selected individual investment options to form their portfolios over the five, ten, and fifteen year periods ending December 31, 2012.”

The gap isn’t huge, but individual asset allocation plan investors earned 1.06% more, on an annual basis, in their retirement plans, than investors with non-asset allocation funds.

Hancock says it’s all about diversifying via “a single choice” – a term you rarely hear from Wall Street when discussing asset allocation investing.

But individual asset allocation portfolios aren’t exactly new, and they are becoming widely available in most 401k plans.

Many such funds come under the banner of “One Choice Portfolios”, i.e. signature target-date and target-risk asset allocations fund-of-funds that offer automatically diversified investment solutions in a single portfolio.

By and large, asset allocation portfolios help 401k plan investors diversify by investing in myriad mutual funds through a single investment. The funds typically include a mix of stock, bond and money market mutual funds based on the portfolio’s objectives.

That mixture makes portfolio diversification a “one step” process, and one can hope it makes things easier for 401k plan participants looking to spread their money – and their risk – around.

Certainly, they’re worth looking into – but know what you’re looking for. Asset allocation funds usually come in two categories:

Risk-based asset allocation fund: A portfolio that matches your comfort with market ups and downs. This fund aims to rebalance to stay at a balanced risk level, and you decide what that risk level should be.

Time-based asset allocation fund: A portfolio based upon a future date when you plan to start using your money. This fund is adjusted automatically to grow more conservative as you get closer to your retirement date.

If you find yourself buried under a blizzard of different funds in your 401k plan, give asset allocation plans a closer look – especially since they offer more performance, according to John Hancock, than the traditional blend of funds that comprise most 401k plan portfolios.

As always, good luck, and good 401k savings – and I’ll see you next week.

Brian O’Connell is an investment analyst at Investing Daily, and the editor of the 401K Millionaire. An ex-Wall Street bond trader, he has appeared as an expert financial commentator on CNN, NPR, Fox News, Bloomberg, CNBC, C-Span, CBS Radio, and many other media broadcast outlets, and is the author of two best-selling books on retirement investing.