It is the time of year for predictions and I’ll make one: You will be better off ignoring the Wall Street stock market predictions for 2020.

Strategists, some of whom are smart, are issuing precise predictions for where the market will be in 12 months and they look authoritative.

In fact, many Wall Street strategists are flagrantly inaccurate. Paul Hickey, a co-founder of Bespoke Investment Group, compared the annual Wall Street consensus forecast in late December with the actual level of the S&P 500 one year later. He found that the forecasts were often off by staggering amounts, especially when an accurate forecast would have mattered most. In 2008, for example, when stocks fell 38.5%, the median forecast was typically cheery, calling for an 11.1% stock market rise. That Wall Street consensus forecast was wrong by 49.6 percentage points, and it had disastrous consequences for anyone who relied on it.

But there is a more reliable and a simpler way to make investing decisions, one that doesn’t rely on putative forecasts. It is based instead on long-term historical data on the broad returns of the stock and bond markets.

They show that stocks outperform bonds over extended periods, but that stocks are far more volatile than bonds. Holding both stocks and bonds makes sense because they tend to buffer one another.

Investing over the long run through low-cost index funds in a broadly diversified portfolio is a reasonable approach for most people. This is standard wisdom among many experienced hands in investing, and Jack Bogle, the founder of Vanguard, made it a viable strategy for great masses of people by starting the first commercially available index fund. Of course, Warren Buffett recommends this approach. And so does David Booth, co-founder of the firm Dimensional Fund Advisors and the benefactor for whom the University of Chicago Booth School of Business is named.

Booth doesn’t make market forecasts, nor does his company.

“We don’t try to forecast the future,” Booth told me in a recent conversation. “We have no ability to do it. Nor does anyone else.”

Instead, Booth said, forget the forecasts — and forget about the news, too. Keep it simple. Don’t try to outsmart the market.

“When you have some money to invest, put it into low-cost, diversified index funds,” he said. “Find a stock-bond mix that you are comfortable with. And if you realize you’re not comfortable, change it until you are — and then stick with it for years.”