So, where is the bounce the economy was supposed to get from cheap gas at the pump?

Some analysts argue that consumers have simply been pocketing the extra money they have been saving on gas, using it to pay down debt or bolster their savings. Others have a far gloomier story to tell.

Jim Bianco, president of Bianco Research, argues that falling oil prices is largely the result of a quickly slowing global economy and may not be an opportunity for faster growth here at home. He put together the following chart, which shows the relationship between the price of WTI crude and expectations for global growth:

Here’s what Bianco has to say about the correlation:

The recent high in crude oil was $107 on July 23. It is now 58% off that high. Only two other declines were similar in magnitude, the 1986 collapse and the post-Gulf War collapse in 1991.

What is happening to crude oil is epic and historic. Moves of this magnitude are not random noise. Something changed to cause this to happen. This is what economists do not understand. They think this was either a random event or a supply glut even though none of the supply data supports this idea.

Bianco argues that the falling price of oil is simply the result of a quickly slowing global economy. But others aren’t so sure. Neil Dutta, head of economics at Renaissance Macro Research, writes in a note to clients that the decline in gas prices shouldn’t have been expected to effect retail sales in December, as his models show that consumer spending is affected by gas price changes only after about six months following the change in price. Therefore, “the tailwind from gasoline is more of a 2015 story than a 2014 one,” Dutta wrote on Wednesday.

Meanwhile, Jim O’Sullivan of High Frequency Economics, points out that Wednesday’s disappointing retail sales numbers come following several months of better than expected reports. In addition, O’Sullivan wrote in a note to clients Wednesday, “There is [no] basis for believing the weakness in December alone represents a change in the trend,” pointing out that in past years, December retail sales data has been unusually weak, “suggesting seasonal adjustment problems.”

O’Sullivan argues that consumer confidence has continued to strengthen, buoyed by falling gas prices. There’s no reason, in his view, to assume that yesterday’s retail sales numbers should be taken as a sign of a slowing U.S. economy.

The difference in these two views is likely a matter of emphasis. The driving force for falling oil is most likely general economic weakness abroad, but that doesn’t mean that some of the decline isn’t also because of increased energy production. And just because growth abroad is slowing, that doesn’t mean that this trend has to seriously crimp economic growth at home. In the U.S., exports account for about 13% of output, and most of those exports go to Canada and Mexico, two places that are not expected to underperform in coming months.

So while declining oil is probably a sign of global economic weakness, the U.S. economy may very well benefit from it in 2015.

Learn more about sinking oil prices from Fortune’s video team: