Robin Hood Math summary

On a late September afternoon in 2023, Brandeis University sent out an email that no school ever wants to write. Their ranking in the US News & World Report’s Best Colleges list had slipped – and not by a couple of spots, either. They’d fallen 16 places. From number 44 to number 60. It was a gut-punch. Parents fretted, alumni groaned, and students asked themselves: “Did my school suddenly get worse?” 

But in reality, Brandeis hadn’t changed at all. What had changed was the recipe – the secret weighting system that US News uses to cook up its annual list. That recipe is as good a place as any to get into the concept of weighted sums, which is something you’ll find being put to use in many of the algorithms that affect your life.  

For those sought-after college rankings, it works like this: the magazine picks common factors – such as graduation rates, faculty pay, alumni donations, peer assessment, and class sizes – and then decides how much each factor counts. That second step – the weighting – is crucial. For decades, the single most heavily weighted factor has been “peer assessment,” a survey of how other college administrators feel about a school. It carries 20 percent of the total weight, meaning it matters more than things like student debt, retention rates, or test scores.

In 2023, US News made the biggest adjustment in its 40-year history. It shuffled weights around and some factors like alumni donations and class-size were de-prioritized. As a result, some schools climbed while others sank. For Brandeis in particular, losing the class-size factor hurt most of all.

What should stand out here is that rankings like these don’t reveal any hidden, objective truths. The different weights being placed on different factors are choices that people are making based on their own set of subjective priorities. And when priorities are baked into formulas like these, gamesmanship follows. Many schools have been caught boosting their numbers. Some have paid incoming students to retake the SAT, hoping for higher averages, others have admitted to inflating data. Columbia made headlines when it was revealed it falsified faculty credentials and spending numbers.

But on the bright side, this also means that you have the power to make your own weighted ranking. Imagine you’re choosing between Tufts, UCLA, and Georgetown. Your “factors” might be weather, student-faculty ratio, politics, and basketball. If sunshine has the most weight with you, UCLA will top the list. If political life matters more, Georgetown wins. If classroom size matters most, then Tufts will rise to the top. Same schools, different weights, totally different rankings.

The same kind of math drives credit scores, loan approvals, job candidate metrics, as well as the algorithms curating your social media feed. But you don’t need fancy software to make weighted sums work for you. Just choose the things you value, give them weight, and see where that takes you. There’s a recipe behind every ranking, so use the one that appeals to your specific taste.