Warren Buffett Explains Why ‘Approximately Right’ Beats Being Precisely Wrong in Investing

Buffett has a talent for distilling important financial concepts down to one memorable sentence. For most retail investors, a crucial piece of advice is as follows: “It is better to be approximately right than precisely wrong.”

There’s a subtle edge to it: the most common way investors make mistakes is not by having insufficient information, but by being seduced by precision—getting lost in spreadsheets, models, and forecasts—and then forgetting common sense. That is, the numbers can add up perfectly and still send you flying off a cliff.

The Danger of ‘Precisely Wrong’ 

Investors today have access to more data, forecasts, and analysis than ever before. Stock prices update by the second. Valuation ratios have three decimal places. There are sophisticated risk models and AI forecasts of future cash flows. It all appears to be very scientific and reliable. 

However, the stock market often remains chaotic, emotional, and fundamentally uncertain. If you build detailed, finely-tuned models on top of uncertain and shaky assumptions about future growth rates, interest rates, and margins with complexity, you could end up “precisely wrong” far more often than you think.

Some Common Ways To End Up ‘Precisely Wrong’

• Over-optimized spreadsheets: Changing growth or discount rates by 0.1% turns a $100 “buy” into a negative “sell.” Precision is revealed as an illusion.
• Obsession with formulas: Valuation models like discounted cash flow have their uses, but they are still only estimates. That means garbage in, garbage out.
• Fixation on short-term earnings: Trying to forecast next quarter’s earnings to the cent will often matter less than understanding whether the business will be stronger in five or 10 years.

Buffett isn’t suggesting that analysis is pointless. He’s saying that trying to make uncertain inputs yield certain outputs is dangerous. Precision is not the same as truth.

Buffett famously likes businesses so simple that “an idiot could run them—because someday one will.” That’s “approximately right” thinking put into action: look for situations where you don’t need to have the next few years mapped out just to break even.

How To Be ‘Approximately Right’ in Your Portfolio

You don’t have to be Buffett to apply his “approximately right” approach. Here are a few practical tips: 

• Know your “circle of competence”: Stick to industries and businesses that you can actually understand. If you can’t explain to a friend how the company makes money and what could plausibly go wrong, you’re guessing, not investing.
• Think in ranges: Use “cheap,” “fair,” and “expensive” instead of agonizing over a single “true value.” Leave ample room for error.
• Seek durable moats: Look for predictable cash flows, competitive advantages, and straightforward balance sheets over fads or complex financial engineering.
• Keep your thesis simple: If your reason for owning a stock requires a multi-tab Excel model to justify, it might be fragile. A few honest sentences often work better than an elaborate model.
• Expect uncertainty and manage the risks: You will never have perfect information or insight. Don’t pretend you do. Manage position sizes, diversify smartly, and avoid bets that only work if everything goes exactly as planned.

Buffett’s own investment approach is that he only invests in businesses he understands, he evaluates the long-term economics, and always demands a margin of safety between the price and what he believes the company is worth.

None of that requires exact precision—but all of it requires good research skills, patience, and discipline.