Got a quarter? Can you flip it? Congratulations, you're a stock guru.

For months now, I've been using Motley Fool CAPS to evaluate the Wall Street wizards who rate stocks, and gauge the likelihood that those ratings will pan out. In recurring columns like "Get to Know a Guru," we meet the unsung heroes (and villains) of Wall Street. In "This Just In," we put the experts to the test, determining whether their upgrades and downgrades are worth the virtual paper they're printed on.

Today, I want to step back and see the big picture. Using the full breadth of CAPS to take a snapshot of the Wall Street Wise, I'll lay out for you who's hot, who's not, and, overall, whether these analytical hotshots are smarter than a fifth-grader.

Newsflash: They're not
We often hear the statistic: "80% of mutual funds underperform the market." But until now, it's been hard to fact-check that bit of commonly accepted Foolishness. Fortunately, CAPS does something nearly as good. It records every stock pick made by 172 professional stock pickers, from professional talking heads like Jim Cramer to financial bastions such as Citigroup. It tracks the recommendations' performance, and most importantly, it records whether the picks are beating or lagging the S&P 500's return. So how are the experts doing?

More than half of them are lagging the market. Out of 172 professional players tracked on CAPS, only 49 can claim better than 50% accuracy on their picks.

Wall Street wall of shame
Fasten your seatbelts, folks, because I'm pulling no punches today. Meet "Wall Street's Dirty Half-Dozen" -- the six least-accurate institutional investors, along with their worst recommendations (that they've made public):

Wall Street Worst Firm

Accuracy

One Especially Bad Recommendation

How Bad?*

Dahlman Rose

5%

Noble Corp. (NYSE:NE)

 8 points

Maxim Group

21%

Corning (NYSE:GLW)

21 points

RBC Dain Rauscher

22%

abitibibowater (NYSE:ABH)

50 points

Capital One Southcoast

33%

Chesapeake Energy  (NYSE:CHK)

32 points

Punk, Ziegel & Co.

33%

National City (NYSE:NCC)

22 points

Fox Pitt

33%

American Express (NYSE:AXP)

12 points

*Which is to say, how badly is this active pick underperforming the S&P 500?

Now mind you, these analysts aren't always wrong. On (rare) occasion, they do find fabulous winners, and in the unlikeliest of places -- such as Punk Ziegel's counterintuitive bet on Wells Fargo (NYSE:WFC) last year, a bet that's beating the market by a good 30 points. Yet on average, even the "best" of the six firms named above guess wrong twice as often as they do right. Pardon my bluntness, but notwithstanding the odd winner or three, I think you're better off flipping a quarter than paying these analysts for investing advice.

Lies, damned lies, and statistics
Confession time: The numbers above certainly suggest that the old truism about mutual funds, and the professionals who run and market them, holds true. But in a new service like CAPS (still in beta, by the way), there are bound to be bugs in the system.

Some such "bugs" are intentional, such as our decision not to permit ratings on "half-penny" stocks with market caps of less than $100 million, or stock prices under $1.50 per share. Some are not -- glitches in the system which may unintentionally affect the statistics CAPS generates. So before the analysts named above cry bloody murder, let me extend the following olive branch: We're listening.

If you've got a gripe about your rating, and the facts to back it up, we'll work with you to fix the problem. Drop our CAPS feedback board a note, and we'll give your arguments a fair hearing. On the other hand, if you're just mad because we're highlighting statistics that you'd rather not advertise, there's not a lot we can do for you.

Well, actually, there is one thing. Just like anyone else, you're welcome to subscribe to Motley Fool Income Investor, where 67% of our active picks are beating the market. This offer gets you Fool access free for 30 days.

Fool contributor Rich Smith does not own shares of any company named above. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 720 out of more than 115,000 players. Chesapeake Energy and American Express are Inside Value picks. The Fool owns shares of American Express. The Fool has a disclosure policy.