The United States government allows for several kinds of tax credits and deductions that can be claimed as exceptions to the general necessity to pay the fees required of the Federal Insurance Contributions Act (FICA). These tax credit exemptions are applied to various kinds of professions. These eligible professions may be determined in slightly different ways according to the state where the claimant lives.
The categories under which tax credits and deductions may be claimed from the obligatory FICA Social Security payments can generally be found in fields which are not known or designed to deliver high profit margins to their operators or participants, such as institutions involved in education past the level of college.
On a similar note, medical students actively engaged in trying to obtain certification as physicians can also be extended a tax credit through the lapsing of a requirement to pay a Social Security fee.
For instance, graduate students can generally claim a tax credit, as can students in general who are also employed by their educational institution, such as through a student work program or some other kind of employment which does not alter the primarily educational basis of their position.
People who are employed by organizations in academe without being students of those organizations will generally not be covered under tax credits and deductions from the FICA Social Security mandated payments in that their relationship to their employer does not differ appreciably from that of that of any employer and employee in the commercial world.
Institutions which are not by nature focused toward profits but which are still generally not eligible for tax credits and deductions in terms of the obligatory payments for FICA are those defined as charitable or non-profit groups.
The ability to secure tax credits and deductions for people who are not citizens of the country will generally vary according to the exact nature of their status in the country. For example, legal aliens who are also considered residents of the United States will generally not be able to claim any kind of tax credits to prevent them from having to pay the Social Security tax.
In fact, generally such "resident aliens," as the government refers to such people, are treated as holding effectively the same status as full-fledged US citizens for the purposes of the country's system of taxation.
On the other hand, legal aliens living permissibly inside of the United States without being considered residents can be allowed to receive tax credits and deductions from the mandated Social Security payments if they are in the country for the purpose of pursuing studies on at least a part-time basis.