Get ready to buy. Our most reliable technical indicator—one that has historically been 99% accurate—is  suggesting that stocks are poised for a major breakout.

Bangladesh butter production surged in February, as moderating grain prices allowed Bangladeshi dairy farmers to boost production by getting higher milk yields from their existing stock of cows. Meanwhile, butter production in neighboring India dropped significantly in February, as a change in government farm subsidies forced Indian dairy farmers to cull their herds. With Bangladeshi butter production set to rise further, we should be looking at a massive rally in the S&P 500 throughout March and April.

By now, I sincerely hope you realize I’m joking.

Whether the S&P 500 goes up, down or sideways over the next two months will have absolutely nothing to do with the Bangladesh butter indicator. But in a paper published two decades ago, David Leinweber and Dave Krider found that butter production in Bangladesh had the tightest correlation to the S&P 500 of any data series they could find. It wasn’t GDP growth…it wasn’t earnings…it was Bangladeshi butter, which “explained” 99% of the S&P 500’s movements.

The authors weren’t quacks. They knew the correlation was a random coincidence and completely meaningless. But they published the paper to get a good laugh and to make an important point about number crunching. Correlation does not mean causation, and if your model doesn’t make intuitive sense, it’s probably bogus.

I’m not bashing quantitative models here. Done right, they can help you build a really solid trading system. Various value and momentum models have been proven to work over time. But the trading system needs to reflect some sort of fundamental reality or it’s one (small) step removed from voodoo.

Adam O’Dell touched on the same idea two weeks ago in Economy & Markets. As Adam wrote, “Computers, databases and statistically sound algorithms can only refine the discovery and implementation of a fundamentally sound investment strategy. At the end of the day, computer algorithms or not, you still need a rock-solid investment strategy.” The model isn’t the strategy. It’s a tool to help you execute; nothing less, nothing more.

Whenever you see someone touting a trading strategy, ask them to explain why it works. Back-tested returns aren’t good enough. If they can’t explain the fundamentals behind their model, it’s probably a matter of time before they blow up.

Oh, and one more thing about Bangladeshi butter. Leinweber wrote in Forbes a few years ago that he still gets phone calls—20 years later—asking for current butter production figures.

This article first appeared on Economy & Markets.

Charles Lewis Sizemore, CFA, is chief investment officer of the investment firm Sizemore Capital Management and the author of the Sizemore Insights blog.

If you Google the phrase “Butter in Bangladesh” you find pages of people talking about a gag paper from 1994, called “Stupid Data Miner Tricks:  Overfitting the S&P 500″. It grew up to be a chapter in the Nerds on Wall Street book, and the  4 minute 12 second video version is part of Jason Zweig’s WSJ columnon data mining. It led to other useless results linking finds of buried treasure to market returns.

My colleague Dave Krider and I thought it would be funny to let the computer churn on a (big by 94 standards) data base sent out by the UN. We deliberately excluded all financial indicators. Things like number of plumbing fixtures, and various agricultural statisitics. Lo and behold, we found that the best single predictor of the S&P500 was Butter Production in Bangladesh.  This became something of a meme, not in the class of Gangnam Style  (the first YouTube Video to pass 1 billion views, if you’ve been in cave) or even One Pound Fish (only seven miliion views of a guy selling fish that got him a record deal), For the impatient, jump to 0:27 to hear the song.

This butter in bangladesh connection has many positive aspects. I have the dubious distinction of being a magnet for wacky market prediction studies, and I have to admit I don’t mind much at all.

I got an early look at a paper by two Russians explaining that the market EXACTLY followed the US population of nine year-olds for about ten years, and then, when the model crashed, interpreted this as a clear sign that the Census Bureau had somehow screwed up the way they count nine year-olds. Get your own free copy of “Exact Prediction of S&P 500 Returns” here.

An earlier (and still the most read) post here on Forbes was “The Economic Indicator in your Pants”  linking economic growth and penis dimension. Inquiring Minds Want to Know.

The year-end clean-up brings another gem, this one from CSFB electronic trading guru, Dan Mathisson. He wrote about the concern over unscheduled market closures, prompted by Hurricane Sandy, in Why Dead Presidents are Worse Than Hurricanes.

But as I continued my research, I realized a far larger risk than bad weather and bad people lay out there. On June 11, 2004, the markets shut down unexpectedly. The reason? The funeral of former president Ronald Reagan. Less than three years later, on Jan. 2, 2007, the heart of capitalism ground to a halt again. The reason this time? Gerald Ford’s funeral. Anyone remember if the market went up or down on April 26, 1995? Well, it did neither, because it was closed for the funeral of Richard Nixon. It turns out the market has closed 14 times in the past 100 years for funerals, making presidential expiration a far greater risk than hurricanes.

In the old days, the exchange officials were much more laid back about market closures than today. The market closed on July 21, 1969, to celebrate Neil Armstrong’s walk on the moon. It closed on June 13, 1927, to honor Charles Lindbergh’s flight across the Atlantic. And it opened late on Jan. 24, 1925, so members could watch a solar eclipse.

Dan left open the burning question of what these gaps imply for the market. Doubtless, some one else will figure it out, and be wrong, but have fun doing it. Volatility shifts will be examined particularly carefully.

In the meantime, I’m glad to hear the George H.W. Bush, president number 41, says it’s time to “Put away the harps” and he’s feeling fine.  That’s a relief. The day you drive off the fiscal cliff is no time to be testing market indicators.