[BostonCard]

Here are the numbers from football outsiders S&P+ for defense:

Team	Def S&P	Rk	Rushing S&P	Rk	Passing S&P	Rk	SD S&P	Rk	PD S&P	Rk	Succes Rt	Rk	IsoPPP	Rk
Iowa	21.4	26	116.1	22	105.9	46	112.0	28	107.5	49	105.8	46	114.9	26

They are ranked 26th overall (Northwesterrn is 4th, Washington is 10th, Notre Dame 33rd to give you a basis for comparison).  For S&P numbers, 100 is considered the national average, so they are above average in both run defense and pass defense (but better against the run), and in both standard downs and passing downs (again, better in standard downs).  Success defensively is the ability to prevent the opponent from gaining, 50% of necessary yardage on first down, 70% on second down, or 100% on third or fourth down.  IsoPPP is "An explosiveness measure derived from determining the equivalent point value of every yard line (based on the expected number of points an offense could expect to score from that yard line) and, therefore, every play of a given game. IsoPPP looks at only the per-play value of a team's successful plays (as defined by the Success Rate definition above); its goal is to separate the explosiveness component from the efficiency component altogether."  Thus, they are good at preventing plays from being successful and from preventing successful plays from being explosive, but are better at preventing the big play.

BC

[BostonCard]

Here are the numbers from football outsiders S&P+ for defense:

Team	Def S&P	Rk	Rushing S&P	Rk	Passing S&P	Rk	SD S&P	Rk	PD S&P	Rk	Succes Rt	Rk	IsoPPP	Rk
Iowa	21.4	26	116.1	22	105.9	46	112.0	28	107.5	49	105.8	46	114.9	26

They are ranked 26th overall (Northwesterrn is 4th, Washington is 10th, Notre Dame 33rd to give you a basis for comparison).  For S&P numbers, 100 is considered the national average, so they are above average in both run defense and pass defense (but better against the run), and in both standard downs and passing downs (again, better in standard downs).  Success defensively is the ability to prevent the opponent from gaining, 50% of necessary yardage on first down, 70% on second down, or 100% on third or fourth down.  IsoPPP is "An explosiveness measure derived from determining the equivalent point value of every yard line (based on the expected number of points an offense could expect to score from that yard line) and, therefore, every play of a given game. IsoPPP looks at only the per-play value of a team's successful plays (as defined by the Success Rate definition above); its goal is to separate the explosiveness component from the efficiency component altogether."  Thus, they are good at preventing plays from being successful and from preventing successful plays from being explosive, but are better at preventing the big play.

BC