After upsetting Michigan State, Northwestern is back into the NCAA tournament discussion, so it's worth wondering what sort of record NU would have to finish the season with in order to make it. The past two years, NU's non-conference schedule was so weak that they would likely have had to post a winning record in Big Ten play to even have a chance, but this year there are several factors working in NU's favor.
First off, the non-conference slate was much more challenging than in years past. According to the extremely useful site RPIForecast.com (which will be referenced throughout the article), Northwestern played the 29th most difficult non-conference schedule in the entire country. Games against national title contender Baylor and Missouri Valley favorite Creighton certainly helped, but what's boosted the strength of schedule more than anything is the lack of truly terrible teams. NU has traditionally played multiple RPI killers like Chicago State and SIU-Edwardsville, but this year only Texas-Pan American is expected to finish in the bottom 100 of the country in the season-ending RPI. Mississippi Valley State and Texas Southern are apparently the class of the SWAC, helping out NU's cause, and it doesn't hurt that Seton Hall is currently ranking a surprising 5th in the nation in the RPI.
Secondly, the Big Ten is by far the best conference in the country by any metric you look at. A ridiculous nine of the twelve teams in the league are currently in the top 50 of the RPI, and since the RPI is largely based on strength of schedule it's likely that most if not all of those teams will remain in the top 50 throughout the season. That will give Northwestern plenty of opportunities to add more quality wins to an already solid profile.
If Northwestern finishes the season 9-9 in conference play, RPIForecast projects they would end up with an RPI of about 33rd in the country, and its very rare to see BCS conference teams with an RPI that high left out. Additionally, in order to win seven more conference games, NU would need to get a minimum of three wins against RPI top 50 teams, and when you consider NU already has two RPI top 25 wins over Seton Hall and Michigan State, 9-9 would be more than enough to get into the tournament. In fact I think NU fans wouldn't even have much of a sweat on Selection Sunday in that case unless NU suffered a bad loss to one of the bottom 3 B1G teams in the first round of the conference tournament.
So if 9-9 gets NU in relatively comfortably, then it stands to reason they'd have a chance at 8-10. Per RPIForecast, 8-10 would put NU's RPI at around 42nd nationally, which is still pretty good. And NU would still have the two RPI 25 wins, and its possible they'd have no bad losses, assuming they take care of business in the four remaining games against Penn State, Iowa and Nebraska (much easier said than done, of course). In a year where the Pac-12 is historically bad and in danger of getting just one bid, the ACC is down and could get only three, and the Big East isn't its usual dominant self and figures to get a maximum of seven, the time is right for a team with a losing record in the nation's best conference to steal a bid. NU would likely need to avoid a first round Big Ten tournament loss, but I have to think they'd have a chance at the very least.