Dimensional Fund Advisors are a group of advisors who, for a fee, will help the individual investor get access to select mutual funds offered by Dimensional. These mutual funds have been designed using plenty of academic research applied to the stock market, and so far the results have been quite impressive. The funds try to not be constrained by simply classifying themselves as value or growth, and also try to avoid emotional retail investor withdrawals by restricting access to the fund through advisors for the retail investor.

Applying theoretical, back-tested research is not always the best way to work with the stock market, for the markets love to snare in the unwary and take all their cash. However, the markets do follow broad themes that tend to repeat. Thus for example, when pessimism hits the markets, great values are always available. When a bull run is underway, letting it run its course is always a great idea.

The DFA funds tend to be largely passively managed, but they remove restrictions such as removing companies from the index simply because they have grown to a certain size (mid-cap, small-cap and so forth). Similarly, restrictions around value to growth are not applied - instead, backtested formulas are applied to the index, all of which have combined to produce above average returns, handily beating S&P 500 index. Furthermore DFA funds may frequently get into the micro-cap space as well and earn its market beating performance in that riskier category.

DFA funds have over $150 billion invested in them, but because of their passive nature, this is still a small number (for comparison, an actively managed Fidelity Magellan may easily exceed $100 billion for funds under management).

If you can access these advisors through your 401(k) plan, these would be great additions to your portfolio. In a non-taxable account, there is the fees involved for your advisor which will cut into your total returns, so you need to work somewhat harder to find an advisor whom you like.

Overall, if you are planning to invest in index funds, take a good hard look at the DFA option!