The Odds Behind Seattle’s Losing Streak

Mercifully, the Mariners’ historically bad 17-game losing streak is over. Sure, Seattle didn’t play well for the last three weeks, but it found itself on the wrong side of probability on an incredible level.

If Seattle had a 50/50 chance to win every game, the chances that they would lose 17 games in a row can be calculated by using a probability chain. Taking 50-percent to the 17th power results in 0.0008-percent, or 1-in-131,072 odds.

However, the Mariners are not expected to win 50-percent of their games. In fact, they were only favored in two of the games during the streak. This makes the losing streak more likely to happen than the calculated 0.0008-percent, but by how much?

For those not up on their gambling lingo, a money line of +150 means that you would win $150 if you bet $100. The money line from each game can be transformed into a expected winning percentage. The aforementioned +150 line would translate to an expected winning percentage of 40-percent. Logically, if a better bets $100 10 times and wins four out of 10, he would win $600, but he would lose 6 out of 10, $600 total. Therefore, he would break even.

Taking the money lines for Seattle’s losing streak, converting those to an expected win percentage, and calculating the probability chain looks like this:

The bookmaker expected the Mariners to lose 15 of the 17 games individually, but the chances that they would lose all 17 is about 0.01-percent. Comparing that with the number calculated earlier, Seattle was about twelve times more likely to have a 17-game losing streak during that stretch than a .500 team.

The odds were 1-in-10,560, or about the same that a person will get hit by lightning in their lifetime. The good news is that the streak is over. Seattle no longer has to worry about becoming the sixth member of the 20+ club or, worse, passing the 1961 Phillies for the longest losing streak in history (23 games).