Employers use the salary information you give them to make an offer that is acceptable to you. In a way you limit your negotiating ability to some extent. If you are being underpaid and if you give that information to the potential employer, you will continue to be underpaid. Hence you better tactfully avoid the question. Of course, your effort should not upset the employer in any way. At the same time if you are correct in your approach, the prospective employer may also become cautious lest you should get upset.
You may be able to snatch a better compensation package even without disclosing the salary information if you can delay the salary issue or keep it vague at least till the employer decides to hire you. In the absence of salary information, the hiring managers tend to base their offer on your market value rather than your present salary.
Here are some scenarios where your salary history is sought and the probable ways you could respond:
Application form seeks salary history: Many companies seek salary information by providing a separate column for it in the application form. Many online job postings and newspaper ads follow the same policy. Some even warn that your application will not be considered without this information. You can possibly get away by simply ignoring the request and warning. Another safe way is to tell the potential employer that you would discuss the issue in person. On most of the occasions, you may not be considered without the salary history. But if you are successful in marketing yourself well, you may get a call even without the salary information.
Salary issue in the interview: When the interviewer seeks the salary information during the interview, you should either avoid responding immediately or tactfully delay discussion on the issue. You can tell him your concern is about the suitability of the job and your focus is not on the issue of salary. Then you can turn around and ask him how much has been budgeted for the position. You talk in general about the total compensation package instead of a specific figure; and casually tell him that your total current package is in the mid-five figures.
Recruiter's insistence: Recruiters generally seek salary information to avoid a situation where the company and the candidate fail to come to an agreement on the salary. The tactics that work with potential employers will not click with recruiters. Remember that the recruiter works for the company and he shares the information he has with the employer.
When all is said done that companies have a salary range for a position; it is not always sacrosanct. If the hiring manager thinks you are the best fit, he will find ways to give you more.