The qualified expense list has two limbs and stopping at the first one overstates the tax. Section 117(b)(2) covers "(A) tuition and fees required for the enrollment or attendance of a student" and "(B) fees, books, supplies, and equipment required for courses of instruction." The word "required" governs both limbs, so a textbook a syllabus lists is covered and an optional laptop is not. Describing the exclusion as tuition-only is a common error and it inflates the amount a student appears to owe tax on.
Room and board is not on the list, which makes it the ordinary reason a scholarship is partly taxable. Housing and food are real costs and they are inside a college's cost of attendance figure, but they are outside section 117(b)(2). A full-ride award that covers living costs therefore produces taxable income on that portion, usually without any tax being withheld, so the liability appears for the first time when the return is prepared.
The services carve-out is the largest practical trap and most content omits it. Section 117(c)(1) removes from the exclusion "that portion of any amount received which represents payment for teaching, research, or other services by the student required as a condition for receiving the qualified scholarship." So a graduate assistantship stipend paid for teaching or laboratory work is compensation, reported and taxed as such, however the university labels it. The statute allows exactly three exceptions, at section 117(c)(2): the National Health Service Corps Scholarship Program, the Armed Forces Health Professions Scholarship and Financial Assistance program, and a comprehensive student work-learning-service program operated by a work college.
The degree-candidate condition is narrower than the credits, and the asymmetry is genuine. Section 117(a) reaches only a candidate for a degree. The American Opportunity Tax Credit takes its enrollment condition from a different statute, which reaches a degree, certificate or other program leading to a recognized educational credential. So a student in a certificate program can claim the credit and cannot exclude a scholarship under section 117(a). These are two provisions with two different tests, and harmonizing them in either direction gives the wrong answer.
A qualified tuition reduction is a different animal wearing similar clothing. Section 117(d) excludes a reduction in tuition provided by an educational institution to its own employee, and to people treated as employees under the fringe-benefit rules. It is an employment benefit rather than an award: it is limited to education below the graduate level, except that section 117(d)(5) lifts that limit for a graduate student engaged in teaching or research activities for the institution, and section 117(d)(3) subjects it to a nondiscrimination test in favor of highly compensated employees. It is not need-based and it is not competed for.
One taxable dollar can be characterized two ways, depending on the question. The IRS treats a taxable scholarship as earned income for the limited purposes of the filing requirement and the student's standard deduction, which usually helps, while the instructions for the form that computes tax on a child's investment income treat it as unearned income, which can subject it to a parent's rate. The same amount, two characterizations, so the strategy of deliberately including a scholarship in income to free up a credit needs working through on the actual numbers rather than assumed to help.
Why an outside award can shrink a package, in one paragraph. Federal need is computed at 20 USC 1087kk as cost of attendance minus the student aid index minus "other financial assistance not received under this subchapter." An outside scholarship is other financial assistance, and 20 USC 1087vv(i) includes in that term all scholarships, grants and loans known to the institution when the determination of need is made. So a private award reduces measured need by operation of statute, and whether the school responds by cutting its own grant or by cutting a loan is where the real difference between colleges lies. That question is worth putting to an aid office directly.