Outside the Box Scores: Looking back at the 2018 season
Stats that shaped the 2018 season
Sam Kerr scored 16 goals in 2018 for the Chicago Red Stars. (Photo credit: Daniel Bartel/isiphotos.com)
Sam Kerr scored 16 goals in 2018 for the Chicago Red Stars. (Photo credit: Daniel Bartel/isiphotos.com)

With April around the corner, and the NWSL season just a few weeks away, let’s take a closer look back at last year in the league.

Opta, the NWSL’s official stat partner, published an in-depth review of 2018 this offseason, with a focus on quality chances, decision making in front of goal, advanced metrics and more.

Here are a few highlights from Opta’s review for the return of Outside the Box Scores.


Expected Goals (Teams)

The North Carolina Courage, who set records for most regular season goals (53) and largest goal differential (36), of course also led the way in shots on goal and expected goals. They registered 387 open play shots (including blocked shots)—over 100 more than any other team in the league—and 131 shots from set play, 30 more than any other team.

The Courage led the league in open play goals (40), despite scoring less than their expected goals from open play. Their open play goal total was more than any other team’s actual or projected totals.

Of the nine NWSL teams, only the Orlando Pride and Chicago Red Stars scored more open play goals than expected—but success in this department was not an indicator of overall season success. The Red Stars (30) made the playoffs and the Pride (22) finished seventh.

The Courage and Portland Thorns FC finished the regular season tied in set play goals (12), with Portland scoring more than their expected goals, and North Carolina scoring fewer than expected. Defensively, the Courage allowed more set pieces goals than expected (9), and the Thorns allowed fewer (6). But, as Opta points out in their review and NWSL fans remember, none of that mattered in the postseason. The Courage beat the Thorns 3-0 in the NWSL Championship — with Jessica McDonald’s two goals coming on set pieces.

North Carolina’s high-pressure also made the team most direct at moving the ball up the field and winning it back in the attacking third.

MORE | Opta introduces possession framework

Shot Clarity

Opta also added shot clarity and shot pressure to their advanced metrics, and broke down the stats for the 2018 NWSL season.

Opta defines shot clarity this way: “Shot clarity is determined by the number of players (opposition and own team included) obstructing the ball’s path to goal. The qualifier has three levels and is collected for every attempt, depending on the number of players blocking the ball’s path to goal. The goalkeeper is excluded from this count unless they are within two meters of the shooter. Shot clarity is affected by players from both teams, so any player standing in this zone apart from the goalkeeper would affect the level of shot clarity assigned to the attempt.”

Like shot clarity, shot pressure is also determined across three levels. “The levels are decided by the amount of pressure placed on the shooter and the distance the defensive players are away from the shooter,” Opta says.

MORE | Opta defines shot clarity and shot pressure

The Courage led the league with 108 shots taken when one or few players obstructed the goal. Sixty of their shots were “high clarity/low pressure” shots, 23 more than the second-place Red Stars in that category.

Expected Goals (Players)

Red Stars forward Sam Kerr led the league in goals, but she did not lead the league in expected goals. Courage forward Lynn Williams finished the season with 18.84 expected non-penalty goals to Kerr’s 14.64. Williams tallied 13 non-penalty goals (and one penalty goal) in 2018. Kerr was one of a few players to score more non-penalty goals than their expected total, finishing with 16 goals.

2018 NWSL MVP Lindsey Horan strongly outperformed her expected total—netting 13 non-penalty goals, nearly five more than her expected total of 8.09. Eight of Horan’s goals came on set pieces.

Goals Prevented

On the defensive side of the ball, Reign FC goalkeepers Michelle Betos and Lydia Williams finished 1-2 in “goals prevented rate” at 1.65 and 1.39, respectively. Thorns goalkeeper Adrianna Franch came in at third with a rate of 1.33.

While Betos, Williams and Franch all played in 16 regular season games or less in 2018, Washington Spirit goalkeeper Aubrey Bledsoe and Sky Blue FC goalkeeper Kailen Sheridan, played nearly every game and each faced a high number of shots, to lead the league in total goals prevented. Sheridan led the league with 7.38 and Bledsoe took second with 6.96. The pair were also in the top six with their goals prevented rate. Bledsoe’s was 1.23 and Sheridan’s was 1.15.

Opta’s 2018 Best XI:

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