Where Does Supergirl Rank?
Modern society depends on indices that transform thousands of individual opinions into trusted measures for making everyday decisions.
The release of Supergirl has prompted a familiar summer ritual. Before buying a ticket, many moviegoers will glance at Rotten Tomatoes. Within days of a film's premiere, hundreds of professional critics have published reviews, allowing the site to display a single percentage that appears to answer a deceptively simple question: Is the movie worth seeing?
Most of us accept that percentage without much thought. We assume it reflects the collective judgment of professional critics, and for practical purposes it usually does. Yet the more interesting question has little to do with Supergirl. How did hundreds of independent opinions become one number that millions of people trust?
The answer reveals something much larger than a movie website. Rotten Tomatoes illustrates one of civilization's most successful inventions: the index.
First edition comic books displayed at Geppi's Entertainment Museum in Baltimore, Maryland, photographed on June 23, 2007. The collection includes landmark superhero and comic book issues that have shaped popular culture for generations, providing an appropriate visual introduction to a discussion of how films such as Supergirl are evaluated through review indices like Rotten Tomatoes. Photograph by Jllm06. Released into the public domain (PD-self). Source: Wikimedia Commons, "Geppis Museum First Edition Comic Books".
More Than Mathematics
Every critic watches the same film but brings a different perspective. Some assign stars. Others use letter grades. Many write essays without attaching any numerical rating at all. Standards differ as much as tastes. One reviewer reserves the highest rating for masterpieces, while another is comfortable recommending an entertaining blockbuster.
Rotten Tomatoes does not ask critics to agree. Instead, it creates a framework that allows disagreement to coexist with aggregation. Reviews are translated into a common language, classified as either "Fresh" or "Rotten," and then combined into a single measure that estimates critical consensus.
The mathematics behind the Tomatometer are relatively simple. Building an index people trust is considerably more difficult.
Critics must continue writing reviews. Readers must continue believing those critics add value. Studios must continue recognizing the score. Rotten Tomatoes must continue applying its methodology consistently and adapting it when necessary. Remove any of those elements and the index begins to lose authority, regardless of how elegant the calculation may be.
Perhaps the most important lesson is that the Tomatometer does not eliminate opinion. It organizes opinion. Hundreds of independent voices remain exactly that, independent. The index simply transforms them into knowledge that millions of people can use.
Every Successful Index Is a Community
Once you recognize Rotten Tomatoes as an index, you begin seeing the same pattern everywhere.
Financial markets depend on the Dow Jones Industrial Average, the NASDAQ Composite, and the S&P 500. None of these indices emerged naturally. Committees determine which companies belong, how the methodology should evolve, and when changes become necessary. When General Electric left the Dow after more than a century, many investors objected because the company had become part of the index's identity. The committee nevertheless concluded that representing today's economy mattered more than preserving yesterday's membership. Governance, not mathematics alone, kept the index relevant.
Higher education offers another revealing example. Every year prospective students consult the U.S. News rankings to compare colleges and universities. Those rankings combine graduation rates, faculty resources, financial indicators, student outcomes, and reputation surveys into a single ordinal list. The rankings derive authority not simply from statistical formulas, but from a broad ecosystem of institutions willing to submit data, academic leaders willing to participate in surveys, researchers willing to evaluate methodology, and readers willing to accept the results as meaningful.
That participation cannot be taken for granted. When prominent universities challenged aspects of the rankings and withdrew from parts of the process, U.S. News revised its methodology and increased its reliance on publicly available data. The rankings survived because the organization adapted as participation changed. An index that ignores its community eventually risks losing the community's confidence.
The same pattern extends far beyond movies and universities. Stock indices depend on investors accepting them as useful benchmarks. Governments publish the Consumer Price Index because businesses, economists, and policymakers broadly agree that it captures inflation in a meaningful way. Artificial intelligence benchmarks matter only because researchers continue evaluating models according to shared standards. Every successful index is sustained by methodology, governance, participation, and trust.
Perhaps that explains why indices have become indispensable to modern civilization. No one has enough time to read every movie review, evaluate every company, visit every university, or compare every price. Indices compress overwhelming amounts of information into forms that humans can actually use.
Their greatest achievement, however, is not mathematical. Indices succeed because communities agree to contribute information, accept common rules, and place their confidence in a shared measure of reality. The next time someone asks where Supergirl ranks, the percentage itself may be the least interesting part of the answer. The real story lies in the community that made the number possible.
Further Reading
- Rotten Tomatoes. "About the Tomatometer."
- S&P Dow Jones Indices. "Index Mathematics Methodology."
- U.S. News & World Report. "Best Colleges Methodology."