Facebook (NASDAQ:FB) stock has been bruised and battered this year, sliding 15% year to date. The stock's decline comes amid a broader market sell-off that has hit tech stocks particularly hard, as well as mounting privacy concerns following a user data leak in March and a security breach in September. Some investors worry the company's data privacy challenges could be weighing on the demand for its ad products, ultimately leading to slower-than-expected revenue growth.

Next week, the social network will get a chance to put a positive spin on its stock's narrative. Facebook reports third-quarter results on Tuesday. Can the quarterly update help alleviate worries?

Ahead of Facebook's third-quarter results, here's an overview of what to watch.

Facebook CEO Mark Zuckerberg presents 10-year plan at F8 conference in 2016.

Facebook CEO Mark Zuckerberg. Image source: Facebook.

Slowing revenue growth

One area investors want to be sure to check on is Facebook's revenue growth. While the social network's 42% year-over-year increase in second-quarter revenue marked a strong growth rate, it was notably lower than its 49% revenue growth in Q1. 

Investors should expect this trend of decelerating growth to continue, according to comments from Facebook CFO Dave Wehner during the company's most recent earnings call:

Our total revenue growth rates will continue to decelerate in the second half of 2018 and we expected our revenue growth rates to decline by high-single-digit percentages from prior quarters sequentially in both Q3 and Q4.

Wehner pointed to currency headwinds, the prioritization of products with lower levels of monetization than the Facebook News Feed, and efforts to give users more control over their data privacy as reasons to expect revenue growth to come down.

Rising operating expenses

Meanwhile, Facebook expects its trend of rapidly rising operating expenses to persist in Q3.

Expenses jumped 50% year over year in Q2 -- a significant acceleration from a 39% increase in Q1. Based on management's guidance for full-year 2018 expenses to rise 50% to 60% year over year, the social network's year-over-year growth in operating expenses should accelerate further in Q3.

Contributing to the rise in expenses are higher core product and infrastructure costs, bigger investments in safety and security, higher marketing spend, content acquisition costs, and more, Wehner explained.

Looking to guidance

Given the overall widespread attention to data privacy and Facebook's recent highly publicized user data security issues, investors will want to look for as much forward-looking commentary from management as possible to see how the social network expects its business to be affected.

In Facebook's second quarter, management said it expected its expense growth to exceed revenue growth in 2019, pushing its operating margin from around 44% in Q2 toward 35% next year. Has management's outlook for this key metric worsened or improved? Or will this guidance remain unchanged?

Facebook reports its third-quarter results after market close on Tuesday, Oct. 30. 

Daniel Sparks has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Facebook. The Motley Fool has a disclosure policy.