Discovering that your co-worker is paid more than you can feel like a slap in the face, even if you were previously happy with your salary. Finding out about a pay disparity can feel profoundly unfair and can make you wonder if your employer doesn't value you as much as you thought they did.
But before you get angry, take a look at these five legitimate reasons your co-worker might be getting paid more than you:
1. The job market might have been different when your co-worker was hired. The market worth of most jobs fluctuates. In tough job markets, it's much easier for employers to find good people willing to work for lower salaries. If if your co-worker was hired when there were more job openings and few candidates, and you were hired during a market that had slimmer pickings for job seekers, that could explain why you were brought on at different salary levels.
2. Your co-worker might have negotiated better than you did when she was hired. Some people negotiate job offers far more aggressively than others – and some don't negotiate at all. Your co-worker's salary could be higher than yours simply because she asked for more at the time of hiring or made a more compelling case for why she deserved it.
3. Your co-worker might have asked for a raise when you didn't. At many companies, you need to ask for a raise in order to get one. If your co-worker asks and you don't, that could explain your different salaries.
4. Your co-worker's performance might be better than yours. Ultimately, compensation is supposed to reflect value, and it's possible that your co-worker is contributing at a higher level than you are. It can sting to hear that, but people are notoriously bad judges of their own performance relative to other people's. It could also be the case that you're excellent at what you do, but your co-worker is earning more because she's great at bringing in new business or pinch-hitting when your manager is away, or some piece of her work that you don't even see.
5. Your co-worker might be getting some form of hardship pay. If your co-worker's job is particularly difficult or unpleasant – because of her boss, or the hours required, or the particular customers she works with – your employer might pay more to compensate for that. It can be tough to attract and retain good employees who are willing to put up with crazy hours or an excessively critical boss, and many are willing to tack on "hardship pay," even if they don't call it that.
All that said, it's also true that companies have an obligation to ensure they're not paying particular demographic groups less than others. If a company ends up paying most men more than most women making the same contributions, it doesn't matter if that came about because the men negotiated and the women didn't; ultimately, they still have a gender-based pay disparity problem to address.
So, what can you do if you realize that a co-worker is earning more than you but you're both contributing at the same level? You'll generally have a much better chance of getting a raise if you focus on the salary you deserve, independent of what your co-worker makes.*
That means that you'll need to research the market rate for your type of work in your field, in your particular geographic area (since salaries can vary dramatically from region to region). In doing this, you might discover that you're actually paid reasonably well, relative to what you could command somewhere else – regardless of what your coworker is making. But if you do find evidence that you should be earning more, then it's time to begin creating a case for a pay adjustment based on what contributions you've made to your organization above the basic expectations for your job. (Your market research can be part of that case, but it shouldn't be the main foundation of it; that research is more of a reality check to help you decide if there's a pay issue you should be addressing in the first place.)
* The exception to this is if you have a reasonable suspicion that sex discrimination is at play. If that's the case, case you'd want to consult with a lawyer to help figure out the best way to proceed.