Who created rank size rule?

The Rank-Size Rule: It’s All About City Sizes, and One Clever Guy

Ever wondered why some cities are massive while others are just tiny blips on the map? There’s actually a fascinating rule of thumb that helps explain this, called the rank-size rule. And the brain behind it? A linguist named George Kingsley Zipf. Yep, you read that right – not a city planner, not an economist, but a language whiz!

George Kingsley Zipf: The Unlikely Urban Guru

George Kingsley Zipf (1902-1950) was a Professor of German Philology at Harvard. You might think, “What does German have to do with city sizes?” Well, Zipf was one of those brilliant minds who saw patterns everywhere. He wasn’t just about grammar and vocabulary; he was fascinated by how things are distributed in the world, from the frequency of words to, you guessed it, the populations of cities.

From Words to Walls: Zipf’s Big Idea

In 1949, Zipf dropped his big idea in a book called “Human Behavior and the Principle of Least Effort.” Sounds like a snooze, right? But inside was a gem: Zipf’s Law. Basically, he noticed that the size of something tends to be linked to its rank. Think about it: the most common word in a book shows up way more than the tenth most common word. And with cities, it’s similar.

The rank-size rule (or Zipf’s Law, if you’re feeling fancy) says that the second-biggest city in a region is usually about half the size of the biggest one. The third-biggest? Around a third of the size. It’s like a sliding scale. So, if your biggest city has a million people, you’d expect the second city to have around 500,000, and the third to have about 333,000. Of course, it’s not perfect, but it’s surprisingly close a lot of the time. The math? Pr = P1/r, where Pr is the population of the city of rank r, and P1 is the population of the largest city .

Why This Matters (and Where It Falls Short)

This rule is pretty cool because it gives us a quick way to understand how cities are organized. It can help city planners figure out where to focus resources or predict how a city might grow. A balanced distribution of city sizes can also mean a more stable economy.

But here’s the thing: real life is messy. Zipf’s Law isn’t a crystal ball. Sometimes, you’ll have one giant “primate city” that dominates everything, like London or Paris. Other times, history or weird economic stuff throws the whole pattern off. Think of a small town that suddenly booms because a huge factory opens nearby. The rank-size rule is more like a guideline than a hard-and-fast law. It’s a probability model where deviations are expected. Some studies suggest that the rank-size rule is more applicable to developed nations.

The Shoulders of Giants: Zipf’s Predecessors

While Zipf gets the credit for popularizing the rank-size rule, he wasn’t the first to notice this kind of pattern. Other smart folks like Felix Auerbach had seen similar trends earlier, noting that city sizes often follow a Pareto distribution. Mark Jefferson came up with the idea of the “primate city,” and Brian J.L. Berry talked about the whole “urban system.” These guys paved the way for Zipf’s big idea.

The Bottom Line

So, who created the rank-size rule? The spotlight shines on George Kingsley Zipf. He took a simple observation and turned it into a powerful tool for understanding how cities work. It’s not a perfect rule, but it’s a fascinating glimpse into the hidden patterns that shape our world. And it all started with a linguist who was curious about everything!