Northwestern’s 93-81 win over Indiana on Sunday gave the team its first Big Ten win of the season. That NU’s first conference win came at home isn’t surprising given the team’s track record – six of NU’s seven conference wins last season came at Welsh-Ryan Arena. What’s strange is the Cats didn’t play better defense in their winning effort.

NU’s improvement over the past two years has been largely driven by a more productive offense, but this offense has been consistent, home or away. The reason for NU’s problems away from home (they were 1-8 in conference road games a year ago) has been defense.

For the Cats, home court advantage seems to show up exclusively in their defensive performance. In home conference games last year, NU’s defensive rating was 108 in points allowed per hundred possessions. At away games that stat shot up to 118.

This stark contrast wasn’t simply due to playing tougher teams on the road.

NU’s worst defensive rating of the season last year came in a road loss to Penn State, and the team continued to struggle in away games against Iowa and Indiana. At Welsh-Ryan, where improved defense helped NU to clinch upsets of Purdue and Illinois, it was a much different story.

The pattern hasn’t been as well-defined in NU’s initial conference games this season, mostly because the defense has struggled mightily regardless of the venue. However, the Cats’ best defensive game against a Big Ten opponent so far came in a home loss to Michigan State in which they allowed the Spartans only 93 points per hundred possessions.

Though there is no universal explanation for the phenomenon of home court advantage, a supportive crowd certainly plays a part. Familiarity with the surroundings, even down to the brand of the basketball used, likely helps the home team as well.

There’s also evidence that home court advantage is more than just a state of mind. A 2003 study by Northumbria University found that male soccer players had higher levels of testosterone before home games than before away games.

The specific reasons for NU’s home court advantage isn’t clear either. Looking again at last year’s numbers, no single component of NU’s defense was drastically improved by playing at home. The Cats generally forced turnovers at a higher rate, held opponents to a lower field goal percentage and sent opponents to the line fewer times in home games, but these individual changes were each relatively small and statistically insignificant. Yet, somehow, the combination of those small upticks yielded a drastic improvement in NU’s overall defense.

NU’s exceptional offensive efficiency against Indiana suggests the Cats are back in prime shooting form after a tough stretch in early conference play. Still, without improved defense, especially in crucial road games like Sunday’s matchup against Iowa, a potent offense might not be enough to reverse NU’s road woes.