The debate about university access tends to assume the barrier is cost. Cost is a barrier. It is not the only one, and the research on what actually changes application behaviour has produced some genuinely surprising results.
The undermatching finding
Undermatching describes a student who applies to and attends an institution substantially less selective than her attainment would support.
It has been documented repeatedly, and it is concentrated among high-attaining students from lower-income households and from schools with little history of sending students to selective institutions.
The size is not trivial. Studies in the United States have found that a large share of high-achieving low-income students apply to no selective institution at all, despite being competitive for admission and despite the fact that selective institutions frequently offer more generous financial aid than the less selective institutions these students do apply to.
That last clause is the important one. In many cases, the institution the student did not apply to would have cost her less.
Why information is the binding constraint
Several things are simultaneously true and difficult for a seventeen-year-old to know.
Sticker price is not net price. Published tuition figures at selective institutions bear little relation to what a low-income student actually pays after need-based aid. Surveys consistently find students and parents substantially overestimate net cost.
Admission probability is opaque. Students at schools with no tradition of selective applications have no local base rate to reason from, and frequently overestimate the required attainment considerably.
Application mechanics are non-obvious. Deadlines, fee waivers, aid form timing and the number of applications that is normal are all things students at well-resourced schools learn ambiently and students elsewhere do not.
What the experiments found
The most cited work in this area involved mailing high-attaining low-income students a packet: information on net costs at a range of institutions, guidance on the application process, and application fee waivers.
The intervention cost a very small amount per student. It produced measurable increases in applications to and enrolment at selective institutions.
Other information experiments have found smaller or null effects, and the field has become appropriately cautious about the size of these results. Simplification interventions — helping families complete aid forms directly rather than merely providing information — have generally produced larger and more reliable effects than information alone.
The pattern across the literature is reasonably clear: reducing the number of steps a family has to complete correctly works better than telling them what the steps are.
Where gender enters
Women now enrol in and complete university at higher rates than men across most of the developed world, so raw access is not the gap.
The gaps that persist are in where and in what.
Field selection is the substantial one, and it is addressed in this section's article on subject choice. But there is also an institutional-selectivity dimension: several studies have found that among comparably qualified applicants, women are somewhat more likely to apply to institutions below their attainment level and somewhat less likely to apply to the most selective options.
The proposed mechanisms overlap with the self-assessment literature — the requirement for a larger margin of expected success before making a claim. The evidence for this specific link is suggestive rather than settled.
The practical checklist
For a student or family navigating this, the questions that carry the most weight are narrow.
What is the net price, not the sticker price? Most institutions publish net price calculators. The numbers frequently surprise people, and in the direction of being lower.
What is the actual admission rate for someone with these grades from this kind of school? Institutions publish entry profiles. Estimating from local reputation is unreliable.
Have the aid forms been filed, on time, completely? This is the single most common failure point and it is purely procedural.
Is the application list balanced? A list with no ambitious options guarantees no ambitious outcome, and the marginal cost of adding one is usually a fee waiver.
What information cannot fix
It is worth being honest about the limits. Information interventions do not address the attainment gaps that precede application, which are larger and much harder to move. They do not address living costs, which for many students are a greater constraint than tuition. They do not address the fact that a student may be needed at home.
What they address is a specific, well-documented inefficiency: students who would be admitted, who could afford it, and who do not apply because nobody told them either of those things.
That is a smaller problem than the whole of educational inequality. It is also one of the very few that has a cheap and demonstrated fix, which is a reason to treat it separately rather than folding it into a larger and less tractable argument.