Religion's Rise and Fall: A Century in Review

Religious adherence can be seen as a choice, like picking a favorite color. Scientists studied 58 religions from 1900 to 2000, using data from the World Christian Encyclopedia. They found 40 growing religions, 11 of which had a big change in the 1900s. 18 religions were shrinking, with 12 hitting their peak in the 1800s or 1900s. They used a special math equation, normally used to describe how crystals grow, to see how religions change. This equation often showed a smooth growth, but sometimes it showed big changes, maybe due to outside influences. Some religions seemed to lose followers, and a few fits didn't match the equation. The study had two main problems: figuring out exactly when a religion started and when it was most popular. Also, the equation might need improvement, especially for shrinking religions.