Merriam-Webster defines a litmus test as "a test in which a single factor (such as an attitude, event, or fact) is decisive."

We are just four games into the Jonathan Smith era of Michigan State football, so the use of the word "decisive" is a bit much. However, this Saturday night's matchup with the No. 3-ranked Ohio State Buckeyes feels like it could be a strong indicator of things to come.

As I outline below in detail, the Spartans have struggled mightily against the Scarlet and Gray for much of the past decade. But the majority of those games came against a Mel Tucker-coached team (or Harlon Barnett-coached team in 2023) or in the waning days of the Mark Dantonio era. Even with a sample size of just four games, I have reason to believe that Smith is a sideline upgrade.

Last weekend's frustrating loss to Boston College made some fans red in the face and others just blue, but that partially obscures the basic fact that the Spartans on balance have played some pretty solid football over the past three weeks, including two road games against solid Power Four opponents.

If the Spartans could have avoided one or two of the corrosive errors last Saturday night, Michigan State could be sitting at 4-0 with two double-digit road wins and possibly a top-25 ranking.

In other words, Michigan State could very well be better than anyone realizes right now.

On the other sideline, Ohio State comes to town with yet another highly touted roster and a 3-0 record, including wins over a cupcake, a doormat and a lost puppy. The schedule was so strenuous that they needed to take a break in Week Three. So far this year, the Buckeyes are the definition of untested.

Then there is the opposing head coach. Ryan Day has only lost eight games total and only three in Big Ten play over five seasons. Yet many observers, me included, find him underwhelming.

Maybe it is just his losing record against Michigan (which is something fans in East Lansing have not seen since the last John Smith), but something tells me that Day may have some more struggles ahead.

In other words, Ohio State could be a little overrated.

When these two elements are mixed together, I think that the outcome could be unpredictable, especially if the experiment is run after dark. What happens if MSU quarterback Aidan Chiles has a turnover-free game and if the Spartans can minimize penalties while maintaining the strong chemistry and execution on defense? The result could be explosive.

There is still a good chance that Buckeyes comes into Spartan Stadium and put up seven touchdowns the way that they did on their last two visits. But somehow I don't think that is the way this game is going to play out.

If Coach Smith can keep up with Ohio State and make this a competitive game into the fourth quarter, that would certainly indicate to me that good things are on the horizon.

The Spartans have squared off with the Buckeyes a total of 52 times going all the way back to 1912, a game in which Michigan State won in Columbus. When the Spartans joined the Big Ten, the series stared in earnest with the Green and White winning four of six games between 1951 and 1966.

But the rivalry has been decisively one-sided ever since. Michigan State has only won 10 times in 45 tries since 1967, leaving the overall series with a record of 37-15 in OSU's favor. That winning percentage of .288 is the lowest for the Spartans against any Big Ten team that has been in the conference longer than six months.

The recent history of the series has been caustic for the Spartans. Under Dantonio, Michigan State was able to get three wins over the five-year span from 2011 to 2015, including a Rose Bowl-clinching win in the 2013 Big Ten Championship Game and in the rain in Columbus in 2015.

But those are the only wins for the Spartans over the Buckeyes this century. Michigan State has not gotten a win over Ohio State in Spartan Stadium since Nick Saban did it in 1999.

The story against the spread (ATS) is not much better. The Spartans are a sour 7-15-1 ATS against Ohio State since the beginning of reliable data in 1997. Ohio State has covered the spread against Michigan State in the last seven meetings by virtue of a 34.5-point average margin of victory.

So, all that is not great.

The spread for this year's game opened at +23 for the Green and White. That puts Michigan State's odds at an upset win at around 5%, which is similar to the odds of a No. 15 seed beating a No. 2 seed in the NCAA Men's Basketball Tournament, not that something like that has ever happened to either school.

The line opened in similar territory for Ohio State's last two visits to East Lansing. Based on my records Michigan State has only been more than a 22-point underdog at home four times since at least 2001 (with the 2016 and 2023 games against Michigan being the other two contests).

Based on all this data, it is tempting to think that Michigan State is going to get blown out. While that certainly may happen, I think that this game might be a lot closer than the Vegas line implies, for the reasons outlined above. I believe the line is inflated due to the recent history in the series, which has little to do with the current rosters or staffs.

My computer tends to agree, at least with the line being inflated part.

Neither I, nor my computer, is bold enough to make the upset pick here, but I have a strong suspicion that the Spartans will cover and play a competitive game. My final score prediction is:

Ohio State 31, Michigan State 18

Table 1 below gives a full summary of the action in the Big Ten in Week Five, including my projected scores, the opening point spread, and the computers' projected point differentials.