American football, basketball and baseball have millions of followers, but they can't match soccer for sheer excitement, says a team of scientists.
The element of surprise elevates football above other sports
The reason is its element of surprise, claim researchers from Los Alamos National Laboratory in New Mexico, US.
Football is more likely to produce an unexpected result, such as a "giant killer" win in the FA Cup.
Scientists analysed results from more than 300,000 games played over the past century.
They reviewed five sports: ice hockey, football, baseball and basketball in the US, and English football.
The team decided to make unpredictability - how often a leading team is overcome by an opponent with a worse record - the best measure of how exciting a league is.
"If there are no upsets, then every game is predictable and hence boring," co-author Eli Ben-Naim told New Scientist magazine.
The results of the analysis showed that the "upset frequency" was highest for soccer, followed by baseball, hockey, and basketball. American football came last on the list, and so was labelled the least exciting sport.
But there was a twist in the tail.
When the scientists looked only at data from the past 10 years, English Premiership football and baseball swapped places.
One interpretation of the finding might be that soccer has become more predictable in recent years.