Watching your co-workers get plum assignments, cash bonuses and public recognition for their work is difficult when you know you're performing at the same level they are. If you and your co-workers are truly performing at the same level, yet your boss doesn't provide you with the same incentives and motivation, they might be receiving preferential treatment. But before you rush to the human resources department with a complaint, look at the circumstances as objectively as possible.

Compare Apples to Apples

To determine whether your co-workers are indeed receiving preferential treatment, you need to make sure that you're doing the same type of work at the same level -- compare yourself only to employees with whom you're similarly situated. For example, if you're a second-year litigation associate, compare your education, experience level and performance to other second-year litigation associates at the firm, not brand new lawyers or lawyers who have been practicing for four or five years. Stick to what you and your co-workers have in common; don't begin comparing non-job-related characteristics, such as age, race or sex.

Note the Differences

Once you establish what you have in common with the co-workers you believe get preferential treatment, take a look at the differences. If you have more experience than others you work with, add that to your draft complaint. Likewise, if you have more academic credentials or professional licenses than your co-workers, include those factors in your list of differences. In some cases, employees receive preferential treatment based on non-job-related factors, such as sex, disability, race or a personal relationship with the boss. List these if you believe your supervisor's slights are based on these factors.

Read the Employee Handbook

Employers' policies often are contained in regularly updated employment handbooks. Review your copy to learn what you need to file a complaint against your supervisor or manager. Many complaint processes start at the supervisory level, but if you believe going to your boss with this type of complaint would become confrontational, it's best to go straight to the human resources department. If you work for a company that doesn't have a dedicated HR department, ask the highest-ranking leader in the company if you can have a private meeting with her.

Just the Facts

In your meeting -- whether it's with HR or the company's top executive -- calmly explain that you believe your co-workers are receiving preferential treatment. Describe the ways that you are similarly situated to your co-workers and then talk about the differences that exist between you and others on your team. Provide concrete examples and facts, not hearsay or rumors. Refrain from complaining about what you believe might be preferential treatment but really is just a personality difference that doesn't affect your job. For example, if your boss routinely asks co-workers to join her for cocktails after work, you might be excluded for any number of reasons. But if you know that co-workers who attend these after-work get togethers usually are given the best assignments or are the first to receive workplace incentives, mention that in your complaint.

Aim For Resolution

If you have ideas for resolving workplace inequities, recommend those to the HR staffer or the company leader. For example, if your last performance appraisal rating should have earned you a 5 percent raise instead of the 2 percent raise you received, ask for an salary increase and retroactive payment. If the company turns down your recommendations or if you're told that the company has to investigate the matter, ask when to expect a follow-up meeting.

No Satisfaction

If you're not pleased with the outcome of your initial complaint and if you believe your supervisor or manager treats you differently, based on non-job-related factors such as those protected by Title VII of the Civil Rights Act, the Americans with Disabilities Act or any other employment law, seek assistance from the U.S. Equal Employment Opportunity Commission or your state's human rights commission. Once there, you'll file what's called a formal "charge of discrimination" so the agency can proceed with an investigation.