It’s big. It’s powerful. It captures the world we live in. And it’s often invisible.
Data exist all around us. Yet most people don’t pay much attention. That may be because we’re used to thinking of data as boring strings of numbers. But when you take a closer look, things get more interesting—and powerful enough to change the world.
In its most simple form, data is a single piece of information. It could be a number, color, age, or name. It’s like a single pixel or drop of ink. But when you combine thousands or even millions of data points, a bigger picture starts to emerge, full of rich patterns and hidden surprises.
Data is behind some of the most impactful public health missions of the 200 years. Here are just a few.
Identifying how cholera spreads
This is the classic example of public health in action. The story starts in 1854, when London was in the grip of a devastating cholera outbreak. At the time, most scientists believed the disease spread through “miasma,” or bad air. But physician John Snow had a different theory—he suspected that cholera spread through contaminated water. Snow mapped cases of cholera and discovered they clustered around a single water pump on Broad Street. After convincing officials to remove the pump handle, the outbreak subsided. His work laid the foundation for modern epidemiology and demonstrated the power of data in solving public health crises. Today, his methodology—using spatial analysis and case mapping—is still widely used in outbreak investigations.
Detangling the link between smoking and lung cancer
In the 1950s, cases of lung cancer skyrocketed, but no one could figure out why. British researchers Richard Doll and Austin Bradford Hill began interviewing cancer patients to try to find the common denominator. Their data showed a shocking result: smoking. Up until then, smoking had been considered a harmless pleasure, and 80 percent of men smoked. Doll’s and Hill’s findings revolutionized the field of public health, eventually leading to tobacco control policies, warning labels, and smoking bans. Since then, smoking rates have declined dramatically, preventing millions of premature deaths.
Revolutionizing heart disease prevention
After the death of beloved President Franklin D. Roosevelt in 1945, Congress resolved to get to the root of heart disease, which was affecting rising numbers of Americans. With federal funding, researchers began studying the health of volunteers from a factory town known as Framingham, Massachusetts. Today, the Framingham Heart Study is considered one of the most influential long-term studies in public health. By tracking thousands of participants over generations, researchers identified high blood pressure, high cholesterol, smoking, and obesity as major risk factors for heart disease. This data has informed national heart health guidelines and encouraged preventive care, drastically reducing cardiovascular disease deaths.
Guiding the COVID-19 response
Remember the color-coded maps of COVID-19 hotspots? Those were made possible by data. Public health agencies worked together to put this data into easy-to-understand maps and charts, share these tools with the public, and make predictions about where the pandemic would hit hardest. Their analysis informed the public health response, including conversations about where to focus resources. Plus, decades of infectious disease research enabled the rapid development of life-saving vaccines.
Fighting the flu
The virus that causes the flu changes constantly. Our bodies don’t recognize the new versions of the virus, which is why we can get it again and again. That’s also why scientists have to make a new flu vaccine each year. This tough task requires scientists to predict exactly how the virus will change in the upcoming year. To do this, they gather data on flu virus samples collected from all over the world. They analyze this data to find patterns and predict how the virus will change over the course of the next year. This complex data sharing and analysis makes the yearly flu vaccine possible.
Tracking germs in wastewater
If you have certain infections (like COVID-19 and flu), bits of germs might end up in your poop. This can happen even if you don’t have any symptoms. As a result, these bits of germs collect in the sewage system. Scientists can take samples of sewer water and look for these microscopic red flags. These data can show where viruses are spreading, even if people haven’t started showing symptoms yet. This helps public health agencies know where to focus communications, testing, and vaccination efforts.
Stopping superbugs
Germs are constantly changing, and some of these changes help them to survive medications that would usually kill them. This is called antimicrobial resistance. The CDC’s Antibiotic Resistance Laboratory Network and the WHO’s Global Antimicrobial Surveillance System collect data on resistant infections worldwide. This information helps public health agencies guide efforts to prevent antimicrobial resistance.
Without data, public health reverts back to the guessing games of the pre-modern era, when we couldn’t prove what caused disease or fathom how to prevent its spread. To protect the lives of people around the world, we must continue to responsibly collect and share public health data. Because data isn’t just numbers: it is power.
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