In my 30-plus years at Vanguard, I’ve said it countless times: “Tune out the noise.”

And it’s not just me. Everybody from Jack Bogle to Warren Buffett will tell you that to be a successful investor, you have to focus on the long term and not get swept up in short-term market fluctuations.

But tuning out the noise doesn’t mean disengaging altogether. In an increasingly complex and interconnected world, it’s vital that investors hear the signal of meaningful information through the static of market chatter.

Investors do benefit from taking note of long-term trends that stand to influence our economies and markets in the years to come. We watch these trends closely, and we discussed our assessment in our recent 2017 economic and market outlook.

Our global economic outlook: Expect stabilization, not stagnation

One trend in particular that we’re watching is the low-growth, low-interest-rate environment that has marked the global economy since the 2008–09 financial crisis. We don’t think this economic backdrop was simply the result of cyclically weak demand or long-term stagnation.

Instead, certain structural forces are contributing: Falling technology costs are limiting businesses’ capital spending, an aging population is weighing on growth in the developed world, and the free movement of capital and products across the globe is suppressing prices and wages. And—despite some of the enthusiasm we’ve seen in markets lately—these forces are likely to continue to dampen growth, inflation, and interest rates.

The upside

I realize this all may sound gloomy, but that’s not how we see it. We expect global growth to stabilize at more modest levels, not stagnate. The world isn’t headed for Japanese-style deflation, in which a widespread sustained drop in prices puts economic activity into hibernation.

In fact, we believe that global growth could pick up modestly over time. Our expectation is based on a potential rebound in productivity as new digital technologies get used more effectively. We also anticipate a slight recovery in the labor force as the baby-boom generation finishes its transition to retirement, nudging up demand for workers.

Prepare for muted returns

And what about prospects for the markets? Vanguard’s outlook for global stocks and bonds remains the most guarded in ten years, given fairly high stock valuations and the current interest-rate environment.

This outlook isn’t bearish but is actually fairly positive when you take into account interest rates that are still low by historical standards.

Making sense of uncertainty amid the future’s shifting tides

Significant trends often happen gradually. Like shifting tides, they’re sometimes barely noticeable at first but ultimately can end up changing the landscape entirely. Other times, apparent trends recede before they have much of a long-term impact. That’s what can make the future so hard to predict. It’s also why you should be skeptical of definitive, pinpoint projections about what’s going to happen.

I know that some investors, especially in the wake of a year marked by political surprises in the United States and Europe, would prefer a little more certainty. But such certainty is bound to be just an illusion.

As Warren Buffett—whose recent shareholder letter featured kind words for Vanguard’s founder—likes to say, “Uncertainty is the friend of the buyer of long-term values.”

All investing is subject to risk, including the possible loss of the money you invest.