Even though McDonald's (MCD 0.37%) stock pulled back 3% after the company reported its fourth-quarter results on Tuesday, the quarter still demonstrated strong fundamental performance from the fast-food giant. McDonald's enjoyed robust comparable-restaurant and systemwide sales growth, as well as sharp rise in earnings per share when excluding the impact of the Tax Cuts and Jobs Act of 2017.

Here's a look at six of the most insightful metrics behind McDonald's fourth-quarter results.

McDonald's drive-through in Denton, Texas

Image source: McDonald's.

1. Growth in systemwide sales: 8%

Putting the spotlight on McDonald's strong momentum, year-over-year systemwide sales growth accelerated in Q4 to 8%, up from 7% growth in Q3.

Since McDonald's reported revenue has been materially impacted by its ongoing strategic refranchising initiative, systemwide sales growth is a good barometer of the company's business growth; it's good to see the metric accelerating.

2. Growth in global comparable-restaurant sales: 5.5%

Unlike growth in systemwide sales, McDonald's comparable-restaurant sales growth decelerated to 5.5% year over year, down from a rate of 6% in Q3 and 6.6% in Q2.

But this isn't necessarily a red flag. This is still strong growth compared to growth in the year-ago quarter of 2.7%, and compared to peers like Starbucks and Wendy's. The two restaurant peers saw comparable-store sales growth of 2% and 3.4%, respectively, in their most recently reported quarters.

Still, with comparable-sales growth declining for a second quarter in a row, investors should keep an eye on this important metric in the coming quarters to see if the notable performance here proves short-lived.

3. Growth in adjusted earnings per share: 19%

On the surface, McDonald's earnings-per-share performance in its fourth quarter was atrocious. At $0.87, EPS was down 40% year over year. But after adjusting for the implications of the Tax Act, earnings per share actually climbed 19% year over year, or 16% in constant currencies.

4. Planned investments: $2.4 billion

Capitalizing on the strong trends it saw in 2017 as the company posted its best comparable-sales performance in six years, McDonald's said in its fourth-quarter earnings release that it plans to invest $2.4 billion in 2018, the "majority of which will be dedicated to reinvesting in our existing locations through accelerated deployment of Experience of the Future in the U.S.," according to McDonald's CFO Kevin Ozan.

A group of young people eating fast food at a fast-food restaurant

Image source: Getty Images.

A big driver of these capital expenditures will be $1.5 billion invested in McDonald's U.S. business to accelerate the pace of its Experience of the Future initiative -- the modernization of stores and implementation of new technology and digital engagement in order to transform the overall experience.

5. Planned new McDonald's restaurants: 1,000

Part of McDonald's $2.4 billion in planned capital expenditures in 2018 will help fund the opening of 250 new McDonald's restaurants. In addition, McDonald's plans to fund the opening of 750 more new stores with its expanded network of developmental licenses and affiliates. This brings total planned new-store openings in 2018 to 1,000.

6. Modernization of McDonald's restaurants: 4,000 stores

One of the other ways McDonald's plans to put this $2.4 billion to work is to modernize 4,000 additional restaurants in 2018.

Looking ahead

As the year plays out, investors should look for McDonald's to make progress toward its long-term financial targets. Chief among these targets are a plan to return $24 billion to shareholders during the three-year period ending 2019, along with systemwide sales growth of 3% to 5% and earnings-per-share growth in the high single digits, both beginning in 2019.