How do you judge if a team is good defensively?

You could look at scoring average against, but then you have to take into account the overall pace the team plays at.   Point differential (how much do you outscore your opponent by) doesn't really help.  If you REALLY suck on offense, you can still be playing good defense, and getting outscored.  Also, a team might play man, zone, press, stall or any combination of the above.  You can have great individual defenders, and still be a  bad defensive team, and you can have NO great individual defenders (just a bunch of solid, smart guys) and still be terrifically successful defensively.

The one constant I've always looked at  is opponents FG% - the lower the percentage of it's shots your opposition is making, the better your defense is.   Of course there will be individual game abberations, but over the course of a season - your opponent converts a high percentage of shots, you're a bad Defensive team.  If they can only convert a low percentage, you're a good defensive team. 

Which is a long way of saying, WOW - did you know we're holding our opponents UNDER 40% from the field?   Opponents are making only 39.5% of shots taken against us this year. 

How is that compared to previous years?

2013:  39.5% (so far- have to see if it holds up.  We do add  Branch and hopefully Sanchez to the mix!)
2012:  44.0
2011:  43.4
2010:  42.8
2009:  44.6
2008:  44.1

Unfortunately, I don't have the team stats for SJU prior to 2008.   Anyone know if they're online somewhere?

CR, maybe this site has the info

http://www.sports-reference.com/cbb/schools/

Easier part of the schedule also accounts for lower fg% I'd guess.

I'd be curious to see at this point in the last several years what the numbers were

CR, I see that these numbers are comparable, but I think you really gotta look carefully at the opponent, and at the strategy for that game. Yes, we held Fordham to 44 points, but we know this wasn't just our smothering d. Actually, it had a lot to do with Fordham setting the pace of the game, and our offense coming out flat.

Norm's teams for the most part, played hard. That was something we could get behind, but when they played a team that had a lot of offensive weapons, like SU, Nova or WV, they'd usually get housed.

CR, I see that these numbers are comparable, but I think you really gotta look carefully at the opponent, and at the strategy for that game. Yes, we held Fordham to 44 points, but we know this wasn't just our smothering d. Actually, it had a lot to do with Fordham setting the pace of the game, and our offense coming out flat.

Norm's teams for the most part, played hard. That was something we could get behind, but when they played a team that had a lot of offensive weapons, like SU, Nova or WV, they'd usually get housed.

I actually think our early season opponents this season were tough overall, even though some don't have the big name.  Fordham was the worst of them and we should have destroyed them.  No excuse there.  We aren't playing well.  Some of the others weren't so bad.  Again, I think it is a matter of finding our consistency more than anything else. Nice seen our team out together two halves of both good offensive posessions as well as defensive.   Need to want to win.

Probably need to weight 3 pt. % vs. 2pt. % to get more accurate picture.

Probably need to weight 3 pt. % vs. 2pt. % to get more accurate picture.

Outside of Baylor and San Fran we have defended the 3 very well I believe.

You need to put that 39% in some context, not just against SJU teams of the past - but against our competition.

We're 11th in a 15-team Big East right now in that category (opponent's fg%).   Good, but not great.
Syracuse and Cinncinnatti (who I know have played some cupcakes) but still are holding opponents under 35% shooting.

Also, CR, if you use the Big East's website and simply change the year manually, you can go back to at least the 2000 season and see team and individual stats.
http://www.bigeast.org/portals/5/fls/19400/stats/mbasketball/2012-2013/CONFLDRS.HTM

I think you will find BE teams hold opponents to lower shooting %s then west coast teams.   Thats my guess.   More fouls, rougher league, less shooters ... could be a combination of factors.   But whereas sub %40 would be very good defense in the Pac12, here it's less than average.   

Also, I don't know where you find them but some of those stats favored by Pomeroy, like Points-per-Possesion .. I think are generally good measures of defense.   

Ultimately though, all that matters is scoring margin.   Do you score more points than you give up?   And ours stinks, second to last in the conference right now.   
We're giving up some easy baskets, whether it's offensive rebounds, or open 3's, and on the other side of the ball we don't move the ball well enough to get easy baskets for ourselves.   

Also, I don't know where you find them but some of those stats favored by Pomeroy, like Points-per-Possesion .. I think are generally good measures of defense.   

Ultimately though, all that matters is scoring margin.   Do you score more points than you give up?   And ours stinks, second to last in the conference right now.   
We're giving up some easy baskets, whether it's offensive rebounds, or open 3's, and on the other side of the ball we don't move the ball well enough to get easy baskets for ourselves.   

I know Stat Sheet has plus minus but I wish regular box scores would list it like the NBA.

You could look at scoring average against, but then you have to take into account the overall pace the team plays at.   Point differential (how much do you outscore your opponent by) doesn't really help.  If you REALLY suck on offense, you can still be playing good defense, and getting outscored.  Also, a team might play man, zone, press, stall or any combination of the above.  You can have great individual defenders, and still be a  bad defensive team, and you can have NO great individual defenders (just a bunch of solid, smart guys) and still be terrifically successful defensively.

The one constant I've always looked at  is opponents FG% - the lower the percentage of it's shots your opposition is making, the better your defense is.   Of course there will be individual game abberations, but over the course of a season - your opponent converts a high percentage of shots, you're a bad Defensive team.  If they can only convert a low percentage, you're a good defensive team. 

Which is a long way of saying, WOW - did you know we're holding our opponents UNDER 40% from the field?   Opponents are making only 39.5% of shots taken against us this year. 

How is that compared to previous years?

2013:  39.5% (so far- have to see if it holds up.  We do add  Branch and hopefully Sanchez to the mix!)
2012:  44.0
2011:  43.4
2010:  42.8
2009:  44.6
2008:  44.1

Unfortunately, I don't have the team stats for SJU prior to 2008.   Anyone know if they're online somewhere?

This is how you judge if a team is good defensively.  http://kenpom.com/team.php?team=St.+John%27s
You look at their defensive efficiency. St. John's is 91st in defensive efficiency.

Possession analysis!!Dean Smith would evaluate his offense and defense by how many points they scored or gave up for every possession. I think his goal were .75 pts. per possession on offense and .65 pts. per possession on defense.He also never evaluated his rebounding by total rebounds but by how many possessions you had. He said there were only three thing you could do on offense, shoot, get fouled and go to the line or loss the ball. If you got fouled and took it out of bounds it was considered the same possession. If you got a lot of offensive rebounds you would have many more possessions. If you are playing against a team that is on fire there will be very few defensive rebounds and the stat sheet will appear that you got killed on the glass but you really didn't.  It's possible to give up say 80 pts  and still have played good Defense if there were say 120 possessions in the game.