Sun, Mar 01, 2009 - Page 9 News List

Algorithms run modern life

Ever wondered why traffic lights turn red when they do or how Google prioritizes its search lists? It’s all done by algorithms — jealously guarded mathematical recipes that increasingly dictate how we lead our lives

By Bobbie Johnson  /  THE GUARDIAN , LONDON

When you last used your supermarket loyalty card, or pulled up just as the traffic lights turned red, you probably weren’t thinking much about math. Why would you? Most of us see mathematics as baffling school algebra that has no application in real life. But you probably meet hundreds of bits of complex math every day without realizing it: the discounts on your loyalty card are the result of deep data analysis, and those traffic signals run on an algorithm that determines when the lights will switch to green.

In fact, large bits of modern lives are secretly underpinned by complex algorithms — the mathematical equivalent of cookery recipes, which take a piece of information and turn it into an action or decision. Algorithms are like computer programs or flowcharts — a sequence of steps that examines what is happening and comes to a conclusion. Take traffic lights: The computer controlling them asks a series of related questions. What time of day is it? When did the lights last go red? Has a pedestrian pushed the button at the crossing? The algorithm guides the computer, step by step, to change the lights.

Algorithms are pervasive, even controlling, in our lives. Book a low-cost flight and an algorithm will determine how much the tickets will cost, depending on supply and demand; arrive at the airport and air-traffic algorithms will determine which place in the queue your plane gets. Watch the weather forecast on TV and the predictions will have been fine-tuned by an algorithm; listen to the radio and the playlist may have been generated by one. Supermarkets, in particular, are a hotbed of algorithms. Almost every aspect of their operation — from deciding the order that products are stacked on the shelves to picking which special offers to run — is determined by a computer.

And since computers are increasingly dominant in our lives, algorithms are increasingly important — and nowhere is this more apparent than on the internet. In the online world, mathematical analysis isn’t just important: the algorithm is king. Everywhere you turn online, companies are using algorithms in their quest for success. From Google’s search results and Apple’s music recommendations to Amazon telling you that “customers who bought this item also bought...” algorithms are at work.

“There is no way, with the size of the internet, that one can do exhaustive searches,” says Marcus du Sautoy, professor for the public understanding of science at Oxford University, and one of Britain’s leading mathematicians. “So you have to rely on mathematics to give you clever and fast ways to get information.”

The British online supermarket Ocado, for instance, analyzes every detail of every activity — from the choices shoppers make to warehouse movements — to make sure there is enough stock in the right places, and to help the company plan future strategies.

“We’re using complicated forecasting algorithms to predict demand,” says Jon Rudoe, head of retail. “The customer sees nothing. It all looks very simple, but it’s actually governed by complex mathematics in the background” — mathematics we can put to use because we now have technology that didn’t exist a decade ago.

Since these recipes have helped internet companies cook up billions in profits, the precise details of the mathematical mechanisms are jealously guarded as among the companies’ most valuable assets. Forget the recipe for Coke or the Colonel’s blend of herbs and spices, these are the trade secrets of the 21st century. And wherever there are secrets, there are people desperate to unlock them. Around the world, countless hours and millions — perhaps billions — of dollars are spent trying to unravel the inner workings of the web’s most powerful algorithms.

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