NWSL Statistical Comparison for 2023

In the same spirit as my last article, I’d like to zoom out even further, and look at some of the league-wide statistics from last year, primarily to see if there are any particular markers in the modern day NWSL that can help predict success. However, success is a little bit hard to nail down, I think, due to how the season played out. We need to include trophy winners, however, I’m not going to include the Challenge Cup, as I think it’s just too difficult to say how seriously the whole league viewed the competition. Gotham were champions, so we should consider their season a success, but I strongly felt like this was a case of everything just falling into alignment at the right time for them. The just snuck into the playoffs as the 6th place team, only making it through on goal differential. In the first round, they played a North Carolina team that was missing Kerolin, by far the Courage’s biggest offensive threat. In the semifinals, they played a Portland team that hadn’t played a game in a month (and Sophia Smith had only played 38 total minutes in the last two months). And in the final, Rapinoe went down injured almost immediately. This is not to say that Gotham are bad, just that I don’t think that anybody (including Gotham) would look at that 2023 team as the blueprint for how to build a championship team. I have a similar conundrum with San Diego, the Shield winners. They never really looked like the best team to me, whenever I saw them play, but somehow, they ended up with the most points at the end of the season. I generally felt like Portland was the best team I saw, even though we eviscerated them in the one game I got to see live, but maybe that’s just because they clearly had the best player in the league in Sophia Smith. They finished 2nd in the standings, and won the 2022 Championship, so let’s call them a successful team too. I’m curious if there are any underlying stats that these three teams have in common.

I’d like to start by looking at goal differential, and then we’ll go further into offense, possession, and defense separately. Goal Differential speaks to the basic premise of football: score more goals than you allow. In straight Goal Differential, we have Portland in 1st with +10, San Diego in 2nd with +9, and Gotham tied for 5th with +1. Expected Goal Differential (xGD) has Portland in 1st with +12.8, San Diego in 2nd with +5.1, and Gotham in 4th with +3.9. So finding our three “successful” teams occupying four of these slots seems like we’re onto something. It doesn’t come as a surprise that good teams have a good xGD, but with Gotham in particular, it says that maybe I should have viewed them as a little bit more of a contender at the start of the playoffs. The team in third place was the Washington Spirit, who had some monumentally bad finishing last year, scoring 26 goals from an xG of 33, thus why they finished so high on the xGD, but missed the playoffs. Had they made the playoffs, it seems very possible that they could have gone on a similar run to Gotham if things started clicking. We also see that Gotham underperformed their xGD by 2.9 goals, so again, they were a better team than the regular season standings showed, and it’s less surprising that they went on a run during the playoffs.

Turning to goal scoring, the Thorns led the league by a wide margin, and the Wave were tied for 2nd. Gotham were actually in 10th place. Interestingly, when we look at xG, things get quite a bit more jumbled. Portland is still in 1st place, but Gotham is in 5th and San Diego is in 8th. If we just look at total shots of any variety, Portland is still in 1st, Gotham is 3rd, and San Diego is 7th. The way that I interpret that is to say Portland were sustainably good on offense. They took more shots, and converted more shots, than anybody else in the league. All the stats seem to support each other with Portland. Gotham also makes sense to me. Their high shot total shows that they were consistently generating chances, but that they weren’t converting them earlier in the season. They were 9th in Shot on Target Percentage, Goals per Shot, and Goals per Shot on Target. But, Midge Purce missed two stretches with injury, coming back into the team on September 2nd. They also signed Esther on August 23rd. It doesn’t surprise me that having those two players in the lineup led to Gotham converting more chances during their playoff run. The final especially bears this out, with Esther scoring and Purce getting two assists and MVP honors. Had Gotham had those two players available for the entirety of the season, I think that we’d definitely have seen them higher in the standings. San Diego, on the other hand, kind of defies understanding. They were very clinical, with the 2nd highest Shots on Target Percentage, and the 4th best np:G-xG (non-penalty goals minus non-penalty xG) in the league. But they didn’t generate a lot of shots, only 7th in the league. They were 10th in Passes into the Final Third, and tied for 10th in Passes into the Penalty Area, 9th in Progressive Passes, and 11th in Progressive Carries. In fact, the only category that they really excelled in was Long Passes, in which they had the 4th most attempts, and the highest completion percentage. Part of how they finished 2nd in Goals Scored is that they do have two good goal scorers in Alex Morgan and Jaedyn Shaw, though it was surprising to see that Morgan was actually last on the team in np:G-xG with -1.7. She’s still a good striker, but I think that we are starting to see a decline from her. Put together, I think this all says unsustainable. I think that San Diego were just flat out lucky to win the Shield last year, and I expect them to get pulled back to the pack in the coming season.

Moving on to Possession. North Carolina won this category in a big way: 59.6% to 54.1% for 2nd place Gotham. The Thorns are in 3rd place, ACFC in 4th, and the Wave in 5th. This is one of the most indicative stats of success, as all of the teams I’m deeming “Successful” fall into the top half. This makes sense to me if you think about possession less as a lot of sideways and back passes, and more in terms of controlling the game. I think that good teams control the rhythm and tempo of a match and force their opposition to be reactionary, and broadly speaking, I think that possession reflects that. When we look at touches, Thorns and Gotham were 1st and 2nd respectively in touches in the attacking penalty area, and 2nd and 3rd in touches in the attacking third (behind Angel City!). The Wave, however, were 10th in both of those categories. On the flip side, the Wave were 1st in touches in their defensive penalty area, and 2nd in touches in their defensive third. So all three teams hang onto the ball, but they do so in very different fashion.

Defense seems to be more indicative of success than offense. Houston had the best defense, conceding only 18 goals. The Wave were tied for 2nd with 22, while Gotham were tied for 4th with 24 goals against. Portland were in 10th with 32. But again, that statistical outlier of Angel City’s 5-1 demolition of Portland at BMO rears it’s head. If we look at xGA, instead, we find the Wave in 1st place with 23.6, the Thorns in 3rd with 26.4, and Gotham in 4th with 26.8. Portland actually had the worst PSxG+/- (Post Shot Expected Goals Plus/Minus) in the league with -3.5, basically saying that they allowed 3.5 more goals than we’d expect based on the quality of the shots they faced. So as a whole, Portland actually played pretty good defense, it’s just that Bella Bixby had an uncharacteristically poor season. The Wave had the best xGA in the league and above average goalkeeping (+2.9 PSxG+/-), while Gotham were 4th in xGA, but actually had the best goalkeeping in the league (+8.7 PSxG+/-). I tend to think of xG and xGA as better predictors than actual scoring, and it seems like that is the case here. I’d also like to highlight an incredibly strange phenomenon with Houston. They were 11th in the league in xGA with 32, yet had the best Post Shot xGA (PSxGA) with 21.8. Meaning that based on where shots were taken, we’d expect 32 goals, but looking at the actual shots it drops to 21.8. That’s a lot of opponents getting the ball in good areas and then blasting it over the crossbar. So yes, Houston had the best defense, but there is no chance they can replicate that.

One final thing that really jumped out to me were the records. San Diego had the league’s best record, finishing 11-4-7, meaning that they dropped points in half of their games, and actually everyone else did even worse. Compared to the European leagues, this is incredible. Last year, Chelseas won the WSL going 19-1-2, Barca won Liga F with a 28-1-1 record, and Lindsey Horan and Vanessa Gilles won Division 1 Feminine with Lyon and a 20-1-1 record. I have heard quite often that there is a lot more parity in the NWSL, but I don’t think I’d fully internalized that before. It’s true, though. In the NWSL, 4th through 7th place were only separated by a single point. The top nine teams all had between 6 and 8 losses. The NWSL is an exceptionally chaotic league, and the ability to turn one loss into a draw, or one draw into a win, is going to make for a big jump in the standings. We just saw a team go from last place in 2022 to winning the Championship in 2023. My point in all of this is that maybe we shouldn’t look too closely at the teams that are currently enjoying success. We could just accept that luck is going to play an outsized role in a league with such fine margins of difference, like the string of injuries that befell Gotham’s opponents on their championship run. That’s not really my personality, but as we saw with San Diego’s 2nd best offense, and Houston’s top ranked defense, luck is going to play a big factor. To conclude the exercise, though, I feel like Portland demonstrates the best model on how to have sustainable success. They scored more goals than anyone, by generating more chances and better chances than anyone. As a team, they defended well, and controlled the match. Ironically they didn’t actually win any trophies last year. That’s the thing about football, though. The best team doesn’t always win, but that means that lots of clubs are in preseason right now, dreaming of lifting a trophy.