How important is it to win the 1st quarter in the WNBA?
Hint: If you’re the Seattle Storm it’s MEGA-important!
We always hear basketball announcers stress the importance of a team starting strong, of winning the first quarter in order to put themselves in a good position to win the game. With the WNBA playoffs in full gear we wanted to see if this philosophy holds true, if, during the 2018 regular season, more games were won by the team that won the first quarter.
Using box scores from the 2018 WNBA regular season, we set out to answer the question: does winning the 1st quarter give a team a better chance of winning the game?
Across the league, the answer is no. In 203 games this season, the team who won the first quarter also won the game 69% of the time.
That sounds promising until you consider how well the other quarters predict the victor of the game: the 2nd, 3rd, and 4th quarters pick the correct victor 69%, 67% and 66% of the time.
The reality is that the team that ends up on top in the final box score tends to win more individual quarters than their opponent. On average, the winning team wins 2.54 quarters per game and the losing team wins only 1.22 quarters, leaving 0.24 quarters that end in a draw.
So while the numbers ever so slightly favor a team that starts the game strong, the 2–3% difference is probably not enough to say that a strong start will make or break a team’s chances of winning the game, especially since winning the first half seems to be equally as important as winning the second half. If a strong start were truly more important, we would see teams winning the game more often when they won the first half.
While we may not see an effect in the league as a whole, what if we calculate a team’s chance of winning the game after winning the 1st quarter by a certain margin?
Let’s look at the outcome of games this season where one team led by at least 1, 5, or 10 points after the 1st quarter:
In general, we see that the probability of winning a game increases as the 1st quarter point differential increases, while the number of games with that point spread decreases. This is true across the league: in sum, WNBA teams went 37–7 when they were up 10 or more after ten minutes; and the trend even holds for lower performing teams such as the Chicago Sky who went a perfect 3–0 when up 10 points.
Amazingly, the Seattle Storm had a perfect win percentage when they had any lead (even just 1 point!) after the 1st quarter. In fact, in 26 games when they were within 5 points of their opponent or better this season, they won 25 (0.96 win %).
Conversely, the Storm only won one game where they trailed by more than 5 points after the 1st period of play. So, for better or for worse, if you’re Seattle, you pretty much know where you stand based on your scoring margin in the first quarter.
It will be interesting to see how far the Storm continue this trend into the playoffs. In their first post-season game on Sunday, they trailed by just 2 points at the end of ten minutes and came out on top at the end of forty minutes.
Seattle will play Phoenix in game two on Tuesday at 10 PM ET. Stay tuned!
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All data scraped from ESPN box scores as of 8/22/18.
