This is more of a thinking-it-through exercise than anything relevant and if it's already been discussed within a different thread, please make a comment and I'll just get rid of it.
I read that strength of schedule should even out among the teams by the end of the year in the comments of that frontpage post regarding the Blazer's having a killer schedule in 2013. Obviously that can't be true in the NFL as teams don't play all the other teams, but I took it for truth regarding the NBA. However, two factors are forgotten when making that assertion.
The first is the conference and division splits. If I remember correctly, EC and WC teams only play each other twice (a home and home). Every divisional team plays each other 4 times. And then every other conference team plays each other 3 or 4 times, to make it to 82 games. I have no clue how they determine those random extra 6 games and am too lazy to research why. Anyway, there is a lot of schedule imbalance going on there. A team like Portland is given the short end because of it's conference membership and then further with it's divisional membership (The NW division has the highest winning percentage at .576, only the Atlantic division in the East has an above .500 winning percentage and that at only .503). Obviously, most Western Conference teams are going to have a much greater strength of schedule than the Eastern conference teams.
The second factor is the fact that the teams don't get to play themselves. Despite being in the same division (and ignoring what 6 extra western conference opponents each team gets) OKC is going to have a weaker schedule than the Blazers. All other factors being equal, OKC swaps 4 games against themselves with 4 games against the Blazers. And while the Blazers have been exceeding expectations, I don't think anybody within a spitting distance of reason can think that the Blazers will be or are a better team than the Thunder. So the Blazers have 4 much tougher games than the Thunder do and will end with a stronger strength of schedule.
These two factors don't even include road trips, back-to-backs, home games immediately after road trips, etc. How great a homecourt advantage do some teams have? Geographical locations for distance traveled, or altitude, or heck, maybe Pacific NW weather gets players not used to it depressed and unable to perform.
Also, teams change throughout the year. Portland's first win against MN would get a greater "strength" score than their latest win (if we determine strength by schedule at the time). But should we take any record without determining the strength of schedule that can be applied to that record? AHH! We end up at circular logic there (I think).
Anyway, nothing too revoluationary here. I guess I conclude that being in the West sucks and being in the Northwest Division really sucks a lot. And I guess I'm of the opinion that a detailed accurate strength of schedule is kind of a crock in general.
Here are the win % just for kicks also (as of 1/8/13)
Atlantic - .503
Central - .447
Southeast - .421
Northwest - .576
Pacific - .520
Southwest - .529