This college search thing can be a little intimidating, especially if you’re going through it for the first time. This is our 30th go-round at U.S. News, so we feel like we’ve got some experience worth sharing.

We’re proud of the fact that, with last week’s launch of the 2015 edition, the U.S. News Best Colleges rankings have now been published 30 times, starting in 1983. Over the years, we’ve improved our information and sharpened our focus, with our primary objective being to help students and their parents make one of life’s major decisions.

There was a big void in that kind of information when we started this project. Colleges, like a lot of institutions, are not always eager to share facts, especially when doing so opens them up to comparisons with their competitors. In the early days, many schools did not want to cooperate with us.

Some education experts said we were making the college evaluation process too simple. We disagreed, and the positive response from our readers assured us that we were on the right track. We’ve played a key role in the years since in making all college information more standard, more reliable and more useful.

U.S. News started the rankings for the same reason we do them today: A college education is one of the most important — and most costly — investments that people ever make. Prospective students and their parents need objective measures that allow them to evaluate and compare schools; the rankings are one tool to help them make choices.

This perspective is more relevant than ever with some private colleges now costing around $250,000 for a bachelor’s degree. At the same time, many public high schools have greatly reduced their college counseling resources, leaving students and parents to educate themselves about the admissions process.

Of course, we have changed our ranking methodology formula over the years to reflect changes in the world of higher education. We make it clear that we are not doing peer-reviewed social science research, though we do maintain very high survey and data standards. We have always been open and transparent. We have always said that the rankings are evolving and not perfect.

The first rankings were based solely on schools’ academic reputation among leaders at peer institutions; in the late 1980s, we developed a ranking methodology in which reputation accounted for 25 percent of a school’s score and important quantitative measures such as graduation and retention rates, average class size and student-faculty ratios, for 75 percent.

Over time, we have shifted weight from inputs (indicators of the quality of students and resources) to outputs (success in graduating students). We operate under this guiding principle: The methodology is altered only if a change will better help prospective students compare schools as they’re making decisions about where to apply and enroll.

It has helped us a great deal to have these principles to focus on as we have faced the inevitable and continuous criticisms from academia about our rankings and their growing influence. One main critique remains: that it is impossible to reduce the complexities of any given college’s offerings and attributes to one rank number.

Indeed, it’s important to keep in mind that our information is a starting point. The next steps in a college search should include detailed research on a smaller list of choices, campus visits and conversations with students, faculty and alumni wherever you can find them.

Feedback from academia has helped improve the rankings over time. We constantly meet with our critics, listen to their points of view, debate them on the merits of what we do and make appropriate changes.

In the process of helping consumers, U.S. News provides colleges a great deal of free exposure to potential applicants; our Internet traffic for education nears 10 million visitors a month, with more than 10 percent coming from foreign countries. U.S. News is on balance helping, not hurting, colleges. And the Best Colleges rankings are a part of the still-evolving higher education accountability movement.

Universities are increasingly being held responsible for their educational policies, how their funds are spent, the level of student engagement and how much graduates have learned. The U.S. News rankings have become the annual public benchmark to measure the academic performance of the country’s colleges and universities.

We know our role has limits. The rankings should only be used as one factor in the college search process and not as the sole basis upon which to choose one school over another. Besides the rankings, we can help college-bound high school students and their parents with a great deal of information on all aspects of the application process, from getting in to getting financial aid. Our website has thousands of pages of research, sortable data, photos, videos and a personalized tool called College Compass.

We’ve been doing this for 30 years, so we know the process is not simple. But our experience tells us the hard work is worth it in the end.

This is excerpted from the U.S. News “Best Colleges 2015” guidebook, which features in-depth articles, rankings and data.

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What We’ve Learned in 30 Editions of the Best Colleges Rankings originally appeared on usnews.com