Remote employees risk being passed over for promotions and high-profile assignments in favor of their onsite peers, experts agree, and research backs them up. That's a big problem for business owners who allow some of their workforce to work from home, as well as for employees themselves. Both employers and employees need to make sure that working from home doesn't equate to hobbling your career.

There's no problem with working from home in an all-remote organization such as WordPress parent company Automattic or (naturally) the remote-work job site FlexJobs. But fairness issues often arise for companies that have some employees working in the office and others working remotely. And that's an increasingly popular model in a world affected by Covid-19. Twitter and Facebook are just the most high-profile companies to make this transition.

Here are some problems that tend to arise in a mixed remote and onsite workforce, and what to do about them.

1. The appearance of lost productivity

Remote employees and their managers should have a clear idea of what employees' tasks are for any given day or week, and they should check in with one another regularly to make sure that work stays on track. That's table stakes for any remote work situation. But what happens when an employee spends a whole workday solving problems for fellow employees, or dealing with an unhappy customer, or making sure a misunderstanding among co-workers doesn't turn into a major problem? All those activities add value, even if they weren't included in the day's original assignments.

If that employee works onsite, chances are his or her boss will have observed what that employee was doing. If that employee works remotely and has uncompleted assignments at the end of the day or the week, it may be harder for the manager to understand what went wrong. This is just one reason why many managers find overseeing remote employees to be a challenge.

The best solution may be for employees to track their activities. And it's important for remote employees and their managers to make sure they discuss these intangible aspects of their work as part of their regular review. 

2. Assigning by line of sight

A work-at-home expert once told me that remote employees sometimes get better and better at doing less and less. That's because many managers tend to give assignments to employees who are in the office, either because they can see that they're available or simply because their physical presence puts them top of mind. Have you ever seen an employee walking down the hall and suddenly realized he or she would be the perfect person to take on the new project you're planning? If so, you can easily see how remote employees may get forgotten.

Managers can avoid this problem with a formal system for assigning tasks and new projects, and by keeping track of what they've assigned to whom. Reviewing that record should make it clear if some employees are getting too many assignments and others not enough. It will also help for employees to have a clear sense of how much time a given assignment should take, and to make sure they alert their managers when they're available for something new. 

3. Liking -- and trusting -- onsite employees more

It's human nature to like and trust people you know well more than people you don't. And no matter how good you are at Slack and Zoom, you will inevitably know the people you see in the office every day better than those who are working remotely. This is a big problem because it's also human nature to give promotions and important jobs to the people you like and trust the most. Adam Bennett, director of Robert Half Technology, told Wired that he doubted any employer would hire a remote employee for a senior leadership role "unless it's deeply baked into their culture."

Even employees with no senior leadership aspirations should spend some amount of time onsite. "Most people think the optimal thing is to have a mixed dynamic where they come into the office one, two, or three days a week to get the social interaction and energy, but not have to show up every day," Zillow founder Rich Barton said at a recent GeekWire event. That may not be practical for employees in different geographic locations. But they should still visit the office whenever they can.