(MONEY Magazine) – April is the cruelest month for tens of thousands of anxious high school seniors. Each day they go to the mailbox looking for responses from the colleges of their choice, either in a thick envelope (containing an acceptance letter and registration forms) or a thin one (with a one-page ''No, thank you''). Anxiety aside, what is especially cruel about today's admissions process is that the coveted fat letters don't always guarantee happy endings: after just a few months on campus, a distressingly high percentage of incoming college students discover that have they picked the wrong school. In a 1987 nationwide poll conducted by the Higher Education Institute at UCLA, nearly one in three first-year students said they would not select their current college if they had the choice to make over again. Why do so many kids end up disillusioned? One reason may be that they base their decisions on information from a single, biased source: the college itself. Virtually all schools tend to paint themselves as the full-color ideal shown above, while playing down the black-and-white reality -- whether it is overcrowded classes, the incidence of date rape or the lack of student housing. ''With declining enrollments, admissions officers are like hotel desk clerks,'' warns C. Wayne Griffith, head of a computerized college-search service in Natick, Mass. ''Their priority is to fill up space.'' So it is up to you to learn as much as you can about prospective schools. Most of the nearly 3 million young men and women who choose a college each year concentrate on factors like location, cost, school size and academic reputation. You shouldn't stop there: press hard for answers to the following seven critical questions so you and your child can avoid a costly disappointment: -- Who does the teaching? Many schools boast during admissions interviews of their prominent scholars and cozy faculty/student ratios. The classroom experience can be very different, however. Ask specifically whether the superstars teach only graduate seminars or lecture in huge amphitheaters. Do the faculty rosters include professors on sabbatical? Those who only conduct research? Some courses may even be run by graduate students. At Arizona State University two years ago, freshman Kim Westley had no instructor at all for her algebra class -- just a workbook and printed instructions. The department no longer offers such ''self-taught'' courses. -- Are many students shut out of courses they want or need? Lotteries and long waiting lists for sought-after classes are common at even the priciest private schools. And because of budget constraints, not all classes are offered every semester. In some cases, a student could be forced to spend an extra year in school just to take courses required for graduation. In California State University's system, some classes are offered only every other year, which is one reason why more than 70% of freshmen take at least five years to graduate. -- Is the campus overcrowded? Dorms are the center of college social life and can provide a protective environment for youngsters not quite ready to live on their own. Yet many freshmen face a NO VACANCY sign. While literature from the University of California at Berkeley concedes that there is ''a high demand for on-campus or near-campus housing,'' it does not state that nearly one in five entering students will be forced to live elsewhere. At Stanford, the accommodations for upperclassmen include 116 three-bedroom trailers (shown above) that have been parked on the campus since 1969. -- Is campus crime a threat? In a recent survey by Towson State University's Center for the Study and Prevention of Campus Violence, more than one in three respondents reported being victims of thefts or assaults on campus during their college years. Yet you will find it difficult to learn the true extent of crime at individual schools. This is the topic school officials are most reluctant to discuss. In 1988, after a Lehigh sophomore was murdered in her dorm room by a male student, the Pennsylvania legislature passed the nation's first state law requiring colleges to compile crime statistics and provide them to anyone who asks. Since then, Florida, Louisiana and Tennessee have followed and 12 other states have legislation pending. If you are concerned about crime, ask about nighttime shuttle-bus service around campus, the size of the school's security force and whether dorms are locked or guarded. -- Will everyone feel at home? Reports of student harassment of Jews, blacks and homosexuals have increased dramatically over the past decade, according to various advocacy groups. The Anti-Defamation League of B'nai B'rith, for example, says that reported incidents of campus anti-Semitism increased from only six in 1984 to 69 in 1989; the league believes that most incidents still go unreported. At the University of Wisconsin two years ago, a fraternity held a mock slave auction. ''There's much less respect for diversity on campuses these days,'' says Kevin Berrill, director of campus projects for the National Gay and Lesbian Task Force. -- Will rising costs far outstrip the available financial aid? For the past nine years, tuition increases have far outpaced inflation at most schools, with financial aid providing only limited relief. Increases at most schools this year will be in the 5% to 11% range; the average increase for private colleges is expected to be 9%. If you're paying the current private-college average of $8,737 this year, steady increases of 9% would mean that your annual tab would top $11,000 in four years, $12,000 in five. And that's not counting room, board and fees, which will also rise. As your costs go up, however, financial aid may not keep pace. Says John Joyce, associate director of financial aid at the College Board, ''You might get an extra loan or help finding a job but seldom more in grants or scholarship money.''

How can you get the answers? The best approach is to undertake your own thorough investigation of prospective schools. If your child already knows what subject he or she will major in, it may be worth talking to the head of that department to learn about the availability of classes. Seek out graduates of your local high school who are attending the colleges on your list, and ask them about the availability of classes and housing. They can also provide important clues about the general atmosphere -- whether partying is more important than studying for example. Be sure to visit the campus while classes are in session. Take the official tour to get your bearings, then go exploring on your own. Walk through classroom buildings checking class size. Eat a few meals in the cafeteria. If at all possible, have your child spend a night in a dorm. That experience can be a lot more revealing than hours poring over the college catalogue. To help you ask the right questions, try reading Choosing a College (Harper & Row, $7.95) by Thomas Sowell, a senior fellow at the Hoover Institution. An academic insider's view of the college experience, this book tells how to cut through rhetoric and identify a school's real strengths and weaknesses.