MSU Hoops Odds Update: Reversals of Fortune

The 2023-24 basketball season is off to a strange start for the Michigan State Spartans. We are just six weeks into the season, and the fortunes of Michigan State have already reserved course multiple times. Even within a single game, the Spartans have looked like a Final Four team one minute and an N.I.T. team the next.

This past weekend at Little Caesar Arena against the Baylor Bears, it was the Final Four version of the Spartans who showed up. That version of the team finally decided to hang around for the full 40 minutes. As a result, Michigan State blew the doors off the No. 6 ranked team in the country.

At the same time, the Spartans have a current record of just 5-5. Michigan State has already taken enough losses to seriously impact the chance at a Big Ten title and a lofty seed in March. Prior to the Spartans' first Big Ten game against Wisconsin, I provided an overview of Michigan State's Big Ten prospects, including expected wins, title odds, strength of schedule, and even Big Ten tournament odds. 

Less than two weeks later, a lot has changed. Michigan State lost two very winnable conference games prior to this weekend's huge win. I have updated the results of each game as well as the efficiency data from Kenpom to arrive at a revised set of predictions for the trajectory of the Big Ten season.  

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Updated Big Ten Standing, Wins, and Odds

With 9% of the Big Ten season complete, it is time to introduce an additional data table that I like to use. Table 1 below is what I refer to as the enhanced Big Ten standings. It includes the current Big Ten record of each team in addition to four other pieces of data. 

First, it contains the current Kenpom rankings and adjusted efficiency margins (AdjEM) for each team as of the morning of Dec. 18. Second, it contains the "plus/minus" for each team. The value is equal to the number of road wins minus the number of homes losses. 

Third, Table 1 lists the current "luck" for each Big Ten team. I define luck as the difference between the actual number of wins and the expected number of wins so far, based on the retroactive spreads derived from the Kenpom adjusted efficiencies of each team. Finally, the table contains the overall strength of schedule advantage/disadvantage relative to the conference average.

Table 1: Enhanced Big Ten standings as of Dec. 18, 2023.

Most of the 14 Big Ten teams played two conference games in December, but Illinois, Wisconsin, Northwestern, and Rutgers each only played one. The Indiana Hosiers are the only school to have won two conference games so far while Michigan State and Iowa are the only teams with two losses.

With so few games played, there is not much to say about the standings. For today, I would like to draw attention to the metric that I label as "luck." Mathematically, "luck" refers to the ability of a team to win toss-up games. 

If a team were to play ten straight games where the point spread was even, the most likely outcome would be a record of 5-5. If that team were to win 7-of-10, one could argue that the team was lucky. Conversely, if the same team went just 3-7 in that stretch, it would be equally reasonable to label that team as unlucky.

If this theoretical series of games were a coin-flipping exercise, the explanation of luck would be completely reasonable (assuming the coin is fair). However in sports, the source of "luck" could also be due to a team being "gritty" with a higher than normal ability to win close games or make winning plays when they count. Luck and grit, in this context, are impossible to distinguish mathematically.

As Table 1 shows, so far Michigan State is the least lucky team in the Big Ten with a rating of -1.15 games. The Spartans were slight favorites in both the home game against Wisconsin and the road game at Nebraska. Michigan State effectively flipped tails in both games.

My analysis of Michigan State's luck is not unique. Kenpom tracks a similar metric that he also labels as luck for all Division 1 teams. Even after the win over Baylor, the Spartans rank No. 357 out of 362 teams in "luck."

So are the Spartans mostly suffering from a lack or luck or a lack of grit? Luck tends to even out, while a lack a grit could be a season-long issue. Prior to the win over Baylor, I believed that the team mostly lacked grit. After the win over Baylor, I wonder if luck played a larger role. The answer to this question will likely determine if Michigan State can challenge for a Big Ten title and approach the level of success that fans expected prior to the season.

Either way, Table 2 below gives the updated Big Ten expected win distribution as of Dec. 17.

Table 2: Updated Big Ten expected wins and win distribution matrix as of Dec. 18, 2023.

Since the start of Big Ten play, Michigan State dropped from second place in expected Big Ten wins down to fifth place. The losses to Wisconsin and Nebraska have resulted in the Spartans' expected win total dropping to 11.36.

A closer look at the table shows that there is a 46% chance that Michigan State finishes the regular season with between 11 and 13 wins. There is a 20% chance that the Spartans win 14 or more games and a 35% chance that the Spartans finish at .500 or worse in conference play.

As for the rest of the Big Ten, Purdue leads the way with 15.7 expected wins, over two wins more than Wisconsin (13.5) and Illinois (13.4). Ohio State (11.8) currently resides in fourth place.

After the fifth place Spartans, there is a two-game gap before a cluster of five teams who are all expected to win roughly nine conference games: Northwestern (9.2), Michigan (9.2), Nebraska (8.9), Indiana (8.8) and Iowa (8.5).

After the Hawkeyes, the bottom four teams are expected to win between six and eight games: Maryland (8.4), Minnesota (7.6), Rutgers (7.3), and Penn State (6.2). If these projections were to hold up through the remainder of the regular season, I would expect only the top five Big Ten teams to qualify for the NCAA Tournament.

Table 3 summarizes the odds for each Big Ten teams to win or share the Big Ten regular season title.

Table 3: Updated odds to win or share the Big Ten title and the win distributions for those winning teams as of Dec. 18, 2023.

The data here naturally mirrors the data above in Table 2. Purdue is still the heavy favorite to repeat as Big Ten champions with a 62% chance to hang another banner. Wisconsin (22%) and Illinois (21%) are the only other teams with more than a 10% chance.

Ohio State has the fourth best odds at 7.6% and Michigan State's odds are now at 4.3%. No other team has odds better than a 1.2%.

Table 3 also shows that if Michigan State were to make a run at a Big Ten title, a final record of 16-4 or 15-5 would likely be necessary. Even then, my calculations suggest that there is a 56% chance that at least 17 wins will be needed.

Strength of Schedule Update

The preseason analysis of the full Big Ten schedule showed that Michigan State had the advantage of owning one of the easiest schedules in the conference. More data has accumulated as more games have been played, but the overall picture is the same, as shown below in Figure 1.

Figure 1: Updated Big Ten overall strengths of schedule calculated assuming an average Power Five team were to play all 14 Big Ten schedules. The total number of expected wins is labeled on each bar.

Ohio State continues to have the easiest conference schedule with Purdue and Michigan State about a quarter of a game back in expected wins. The Spartans' schedule is almost a full game easier than the schedules for Michigan and Rutgers.

At this point in the year, it is perhaps more useful to compare remaining schedules. Figure 2 below shows the strengths of each team's remaining conference schedule (measured by expected win percentages as teams now having differing numbers of remaining conference games).

Figure 2: Updated Big Ten strengths of schedule for the remaining conference games as of Dec. 18 2023.

The good news for Spartan fans is that Michigan State has the easiest remaining conference schedule by a reasonable margin over Purdue, Ohio State and the remainder of the conference. The home game versus Wisconsin and the road game at Nebraska were both in the top half of difficulty on the Spartans' overall schedule. Those games are now both in the rearview mirror.

Michigan State Schedule and Outlook

Figure 3 below summarizes the projected point spread and win probabilities of all of Michigan State's remaining conference games. 

Figure 3: Odds for MSU to win the remaining Big Ten games, based on Kenpom efficiency margins.

Of the 18 remaining Big Ten games, Michigan State projects to be at least a six-point favorite in eight of those games and at least a three-point favorite in 11 of those games. There are four games left on the schedule where the projected line is close to a toss-up (50% to 60% odds), and there are only three games left where Michigan State is likely to be the underdog (the games at Illinois, Wisconsin, and Purdue).

The Spartans will be big favorites in the final three non-conference games (versus Oakland, Stony Brook, and Indiana State) before restarting conference play in the new year with the easiest Big Ten game on the schedule (at home versus Penn State) on Jan. 4. This should allow for the Spartans to build some positive momentum.

Jan. 7 kicks off a tough stretch that will determine if the Spartans can climb back into the Big Ten race or not. The road games at Northwestern (+2), Illinois (-5), Maryland (+2), and Wisconsin (-5) represent four of the toughest seven remaining games. Two easier home games against Rutgers (+9.5) and Minnesota (+11) also fall in this stretch. At worst, Michigan State likely needs to go 4-2 in this part of the schedule in order to stay in the conference race.

In this case, Michigan State would by just 5-4 heading into the first game against Michigan on Jan. 30. While this record would certainly not be comforting to the Green and White faithful, it would not be a disaster. The final 11 games on the schedule are significantly easier with only the road game at Purdue projecting as a likely loss. 

Michigan State could conceivably win 10 of the final 11 conference games to finish at 15-5. That record would place the Spartans in contention for a Big Ten title if Purdue were to slip up a few more times than expected. If Michigan State can steal a victory at Wisconsin or Illinois in January, it could potentially erase some of the damage done in December and put the Spartans in solid shape in the conference race.

Big Ten Tournament Odds

The Big Ten Tournament is still a long way in the future, but it never hurts to sneak a peak at how it might shake out. Table 4 below provides the odds that each team will earn each possible seed in the Big Ten Tournament based on 200,000-cycle simulation of the remainder of the Big Ten regular season.

Table 4: Big Ten Tournament seeding odds as of Dec. 18, 2023. 

Naturally, these odds mirror the expected win data shown in Table 2. Michigan State currently projects as the No. 5 seed in the Big Ten tournament. That said, there are two subtle advantages for the Green and White.

First, if all the projected favorites were to win every remaining Big Ten games, Michigan State would claim the No. 3 seed in the Big Ten Tournament. In this case, the Spartans would win a tie-breaker versus Illinois as the Illini do not get the chance to host either Wisconsin or Ohio State this year.

In a related second point, Michigan State only plays Ohio State once this year and the game is in East Lansing. In essence, the schedule provides a potential tiebreaker advantage over two of the top four teams in the conference, either of which could help the Spartans secure a double bye.

Speaking of byes, Table 5 below takes the data from Table 4 and gives the odds for each team to start the Big Ten Tournament on either Wednesday (no bye), Thursday (a single bye) or Friday (a double bye).

Table 5: Odds for each Big Ten team to start the Big Ten Tournament with a double-bye, a single-bye, or no bye.

The most likely outcome (53%) is for Michigan State to earn just a single bye, but the odds of a double bye (39%) are still quite high.

Finally, Table 6 below gives the odds for each team to advance in the Big Ten Tournament. As a general rule, these odds will track with Kenpom efficiency margins. As of mid-December, Purdue remains the heavy favorite to repeat as Big Ten Tournament Champions, but the field has slight better odds (55%). 

Table 6: Odds for each Big Ten team to advance past each round of the Big Ten Tournament, as of Dec. 18, 2023.

My calculations currently give Michigan State an 8.4% chance to win the Big Ten Tournament (currently fourth best), which is roughly twice as good as the odds to win a regular season title.

That is all the data that I have to share today. Enjoy.