NEW YORK (ETF Expert) -- One of the most commonly cited facts about the U.S. economy is that consumers represent two-thirds or more of GDP growth. Put another way, if Americans are spending, the economy expands. If we rein in our consumption, however, the economy expands at a slower pace and/or contracts.

On Thursday, newswires trumpeted that GDP expanded at a pace of 3.7% between the beginning of July and the end of December. Not only did the economy accelerate in the second half of 2013 -- the first half growth came in at an anemic 1.8% -- but 3.7% marked the strongest second-half growth in ten years. With a government shutdown? With higher interest rates? Surely this demonstrates the remarkable resilience and durability of the American consumer.

On the other hand, there are plenty of conflicting data points regarding consumption. Pending home sales are at their lowest level in more than two years. Meanwhile, annualized wage growth averaged somewhere in the neighborhood of 1.75%-2.0% in 2013, well below the "norm" for personal income growth that is closer to 3.25%. Undoubtedly, many Americans have been feeling wealthier because of rising home prices and/or rising 401(k) values. Nevertheless, the absence of genuine income growth may eventually exact a heavy toll.

Now comes the biggest question of them all: Does any of this matter to the stock market or its key component sectors? Probably. For example, retailers have put forward some of the weakest earnings reports, revenue numbers and forward guidance of any sub-segment. It follows that SPDR S&P Retail (XRT) - Get SPDR S&P Retail ETF Report has been one of the ugliest year-to-date investments with regard to its percentage losses as well as its dip below a long-term 200-day trendline.

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Right now popular consumer investments like SPDR Sector Select Consumer Discretionary (XLY) - Get Consumer Discretionary Select Sector SPDR Fund Report and Vanguard Consumer Discretionary (VCR) - Get Vanguard Consumer Discretionary ETF Report may appear like "buy-the-dip" winners. Still, one has to wonder if we may be witnessing a last hurrah for stocks tied to household consumption.

The long and the short of the current environment may be that U.S. companies, particularly consumer-oriented corporations, may not be able to increase their profit margins by charging more for products. That leaves cost-cutting and share buybacks as the primary ticket for "goosing" results until employment gains translate into wage gains.

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Bearish prognostications notwithstanding, the easiest way to deal with the uncertainty is to monitor a popular consumer barometer like VCR. If VCR falls below and stays below its long-term 200-day moving average - if highly correlated funds like XRT and SPDR Sector Select Consumer Staples (XLP) - Get Consumer Staples Select Sector SPDR Fund Report struggle in the same fashion -- broader market trouble may be afoot. In contrast, if ETFs in this arena can recapture their shorter-term 50-day trendlines, "buy-the-dip" fans will have beaten the bears yet again.

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This article represents the opinion of a contributor and not necessarily that of TheStreet or its editorial staff.

Certified Financial Planner Gary A. Gordon, MS, is the president of

Pacific Park Financial

, an SEC-registered investment adviser in California. He has more than 23 years of experience as a personal coach in money matters, including risk assessment, small-business development and portfolio management, and has taught finance in Mexico, Singapore, Hong Kong, Taiwan and the U.S. He wrote the draft copy for Maverick Investing, a McGraw-Hill publication, and writes commentary for Seeking Alpha in addition to ETF Expert, for which he also hosts the

ETF Expert Radio Podcast.