Last week, Joshua Brown wrote in a blog post that Wall Street analysts blew their analysis of BP (NYSE: BP) because they're a bunch of ... fundamental analysts. Brown, a money manager and blogger, is one of my favorite reads -- always entertaining and to the point. I believe he badly misfired on this one, however.

His post was in response to a Reuters report that nearly every Wall Street analyst stuck to their ratings as the Gulf crisis unfolded. As BP shares began to drop, "most were screaming the same message: buy, baby, buy."

Why did nearly every Wall Streeter miss so badly? Reuters says the BP mess once again exposes "the conflicts and weaknesses that still bedevil the sell-side analyst community, despite a decade of much-heralded reform." In other words, analysts are still hesitant to be negative toward companies that can provide huge amounts of underwriting business.

Santa Clause and the Tooth Fairy
Brown has a different opinion, blaming the blown calls on fundamental analysis, which looks at a company's financials, competitive position, management, etc., in order to come up with a fair value estimate. Contrast that with technical analysis or momentum investing, which ignore a company's fundamentals and focus on stock price movements, trading volume, and other things unrelated to the underlying business.

"For some strange reason," Brown writes about fundamental analysts on Wall Street, "they've been indoctrinated with this belief that Discounted Cash Flow analysis and terms like 'Fair Value' will mean anything at all in a market of buyers and sellers relentlessly seeking advantage over each other." Cutting to the chase even more: "DCF is the tooth fairy, Fair Value is Santa Claus."

Brown says the BP crisis is so full of unknown risks and uncertainties that believing that a fundamental analyst's "model" can provide answers "is the height of slapstick-comedy-masquerading-as-research."

What a Fool fundie believes
Brown misses in two ways here. First, most Wall Street analysts don't even use DCFs to value companies. A survey by NYU professor Aswath Damodaran a few years ago revealed the majority rely on relative valuation -- which is mostly about comparing similar companies to each other and then determining which are undervalued on a relative basis.

But -- Brown's shots at DCF and fair value aside -- that's a rather minor point. His biggest misconception is that fundamental analysis somehow excludes the concept of saying, "No one -- no one! -- knows what BP's bill will be and how long it will be paying," and therefore it's crazy to perform a DCF on the company.

In fact, a fundamental analyst did say that: Tom Jacobs, head of the Motley Fool Special Ops service. His initial research on BP focused on one question: "Is the potential reward worth the risk?" Because of the still unknowable downside compared to a quite limited near-term upside of around 50%, Tom decided the potential reward was not worth the risk and moved on. That seems like sound fundamental analysis to me.

Responsible fundamental analysis most certainly considers risk vs. reward. The fact that nearly every Street analyst failed to get it right speaks more to the still-tangled web of Wall Street relationships than a failure of fundamental analysis.

Foolish bottom line
Things are always so clear in hindsight. Of course Johnson & Johnson (NYSE: JNJ) was an obvious buy during the 1982 Tylenol scare, right? But, in the moment, things aren't always so clear. Seven people died when someone poisoned capsules, and there were fears the company's top-selling product would never recover from the stigma. It did recover, but it took some masterful work from J&J's management to set things right and erase the fears.

A more recent example involves Toyota (NYSE: TM) and its sudden-acceleration problems. In the article "Is Toyota on Sale?," Tom explains how to better analyze these special situations. Whatever the case, if you're going to take on the extra risk in these special situations, you need a lot more upside than what BP is offering. Otherwise, it's just not worth it. Whether you're a fundamental analyst, technical analyst, or fortune-teller.

Fool analyst Rex Moore is staying far away from BP. He owns shares of Johnson & Johnson. Johnson & Johnson is a Motley Fool Income Investor selection. Motley Fool Options has recommended buying calls on Johnson & Johnson. The Motley Fool has a disclosure policy.