Though it isn't 2020 quite yet, companies are already putting dates to their first earnings reports for the year. Coffee giant Starbucks (NASDAQ:SBUX) is among the first. The company has scheduled its fiscal first-quarter earnings release for Jan. 28.

Starbucks will have a high bar to live up to when it reports earnings. The company recently closed out an impressive fiscal 2019, with comparable store sales rising 5% year over year, helped by a 3% boost in average tickets and a 1% increase in transactions. A 7% year-over-year increase in its store count helped, too. Then, of course there's Starbucks stock's 35% gain over the past 12 months. With a gain like this in the rearview mirror, investors are pricing in more strong growth in fiscal Q1 and beyond.

Ahead of Starbucks' fiscal first-quarter earnings report next month, here's a look at some of the key areas investors will want to check on.

A barista holding Starbucks' 2017 Holiday cup

Image source: Starbucks.

Comparable store sales

The key metric for almost any retailer is comparable store sales growth, or sales at stores open for 13 months or longer. This metric provides investors insight into the performance of its business when excluding the impact of new store openings.

Starbucks' comparable store sales growth accelerated in fiscal 2019, growing 5% year over year. This compares to 2% growth in fiscal 2018. For fiscal 2020, management expects strong yet slightly lower growth in the metric. It guided for comparable store sales to rise 3% to 4% year over year.

Investors should look for Starbucks' fiscal first-quarter comparable store sales growth to be within this 3% to 4% range.

Starbucks Rewards

A key driver of Starbucks' business is its digital rewards program.

"[W]e know from experience that when customers join Starbucks Rewards, their spend level with Starbucks increases meaningfully," explained Starbucks CEO Kevin Johnson in the company's fiscal fourth-quarter earnings call. With 17.6 million active members, increased spend from members has a major impact on Starbucks' business.

Given the importance of Starbucks Rewards, investors should look for the program's member growth rate in the U.S. to remain near the 15% growth seen in fiscal Q4.

Mobile order sales in China

Just as has been the case in the U.S., Starbucks' investments in digital are paying off in China as well. The company's reinvigorated Starbucks Rewards program in the country now has 10 million active members -- up 45% year over year in fiscal Q4.

Digital is particularly important in the market because mobile ordering is popular in China. Mobile order sales accounted for 10% of total sales in the country, with seven of these percentage points coming from deliveries and three points from mobile order for pickup.

In fiscal Q1, investors should look for mobile order sales to continue to rise as a percentage of total revenue in the important market, helping comparable store sales growth.

Starbucks will report its fiscal first-quarter results after the market closes on Tuesday, Jan. 28.