Expected Goals and the Gambler's Fallacy

For the Toronto Maple Leafs, the series against the Florida Panthers has had a much different arrangement than the one against the Tampa Bay Lightning. I have two points to make around this. My shorter point is I think the Leafs prepared well for the Lightning defensively with their specialized pairings, but that hasn't worked against a monochromatic Panthers offense. It sadly took Sheldon Keefe two games too many to figure it out. That's one reason I see why the success has turned to failure so quickly.

My longer point is about goals scored vs goals owed. Against Tampa Bay, the Leafs top-six earners in Expected Goals were in order: Matthews, Tavares, Nylander, O'Reilly, Järnkrok, and Marner. Kerfoot was about tied with Marner over six games. They accumulated nearly 12 expected goals. On those 12, they scored 16 real goals. The rest of the lineup scored seven goals, led by Morgan Rielly's three. The Lightning's top six xG players scored seven goals on seven expected, with the rest of the lineup scoring eight goals.

What was the difference in that series? The top six put a margin on the Lightning, both in chances, and by outdoing their expected goals. The rest of the lineup will do what they do, they'll saw off their opponent, meaning how you win is with the top of the lineup. The most dangerous players. And the Leafs did that against Tampa.

Now let's look at the Panthers.

The Leafs top six xG earners so far are Tavares, Nylander, Matthews, O'Reilly, Marner, and Matthew Knies. What jumps out to me right away is that Matthews isn't at the top of the list. The second thing is that Matthews Knies was probably going to tear up this series because he's still ahead of Kerfoot, Järnkrok, Bunting in only a game and a half. Sigh. I miss him.

Anyway, back to the numbers. The Leafs top guns have put together seven expected goals. They've only scored two goals (ROR and Knies). Tavares, Nylander, and Matthews have 5.5 xG between them and haven't gotten a single goal out of it. They've been getting chances at a higher rate than they did against Tampa, but nothing is going in. And it's going to be the poison that does the team in if they can't pull off a miracle.

I don't even need to mention the Panthers offensive numbers because they're genuinely irrelevant when this is the outlook of the top of the team, but I'll give them anyway for posterity. Six goals on five expected. Both supporting casts have scored four goals in the series.

Now to bring a bit of sports analytics (and frankly gambling) theory to this article. There is sometimes a belief that whatever chances a team has produced that doesn't come good is owed to them in retrospect. That the Leafs can expect Matthews, Tavares, and Nylander to make up those five goals on their next five shots.

That's a fallacy; the gambler's fallacy.

The reality is those chances are gone. All we can glean from these numbers are that the Leafs top guys played well enough in the past to win. Except in Game 3, where all the top players except Nylander had terrible games and didn't earn the win at all.

The past is the past, the Leafs are not "owed" the expected goals they have created. All they can do is earn them again and hope they go in.

Unfortunately, like Game 3 against Tampa Bay, once luck swings one way, it's really hard to make it all back up within the period of one series. Three games can be undone over 82 games, but not seven. We'll see how far the luck can swing.

Win four games, how hard can it be?

Maple Leafs Playoffs Analysis