Image source: GE. 

General Electric (NYSE:GE) is set to release its fourth-quarter earnings on Jan. 22 before the market opens. Going into the report, Wall Street thinks the industrial giant's revenue will fall 14.2% year over year to $36 billion and earn $0.50 per share -- $0.06 less than it did a year ago. Beyond the headline figures, investors should also determine how GE's underlying businesses is performing and if the company's transformation remains on track, both of which are integral to its growth prospects.

This time around, there are three main areas to watch when GE reports earnings:

1. Currency headwinds
The U.S. dollar has dragged on GE's results throughout 2015 and investors should expect that to continue in the fourth quarter, as the U.S. dollar was stronger than it was during the year-ago fourth quarter. When the U.S. dollar strengthens, it makes other currencies appear weaker. For a company like GE that generates about half of its revenue overseas, weaker currencies convert to fewer dollars, which in turn, pressures revenue. During the first nine months 2015, the strengthening dollar negatively affected GE's comprehensive income by $2.9 billion.

2. Macroeconomic environment
Between recent market volatility brought on by the continued fall in oil prices and growing concerns over China's economic growth prospects and stock market, GE may face greater challenges driving growth in what's already been a sluggish global growth environment. After all, GE's industrial results are highly correlated to the world economy, especially industrial activity.

During the third-quarter earning call, management eased these concerns by noting that its quoting activity -- a proxy of future demand -- remains at the highest levels the company has ever seen. This message portrayed that GE's industrial products and solutions continue to add to value, despite a volatile global environment.

It's likely that management will address these concerns once again on the conference call tomorrow. But if not, key in to the company's overall order backlog to get an understanding of future customer demand.

3. 2016 outlook
Along the same lines as No. 2, GE is almost sure to provide an operating framework and outlook for 2016 within its earnings presentation as it has in past years. The idea here is to get a sense of what management is promising to investors and holding them accountable when it's time to deliver. The outlook will likely outline its earnings and margin guidance, expectation for each of its industrial segments, goal for GE Capital asset sales, and how much money it'll return to shareholders between buybacks and dividends.

All eyes on Friday
When General Electric reports earnings tomorrow, focus on how the underlying business is performing in areas like sales, margins, and profitability, rather than how investors react to the news. Also, expect continued currency headwinds, an update on the global growth environment, and what management thinks 2016 will hold. Together, these areas will help investors get a better sense of the big picture at GE.