We surely can't have a discussion of shooting skill without considering defensive skills against those shots.  Yes, we see alot of clanging bricks tossed up by wide-open shooters and yes, defense is a foreign concept to some teams and players.

BUT.......overall, I'd have to say that better defense has something to do with the shooting percentages being flat or down over time.  While I have no stats to support my theory...and besides, if a shot is missed we certainly can't statistically track whether it was good defense or poor shooting. I would propose two theories

1. Defense of the three point shot has improved.  The shot itself had its own early evolution (remember how slow Denny was to adopt it?).  The defense of the three also evolved...a curve slightly behind the adoption curve.  Coaches eventually figured out better schemes for defending the 3, especially against certain shooters so it stands to reason the shooting percentages would drop
2. Overall defense has improved.  I believe defenses today are better than ever.  Tubby, Izzo, Rick and others demand a defensive intensity that wasn't always seen routinely in college basketball.  Surely that had an effect on shooting percentages.

Just a thought

most definitely what caused the intial decline in 3pt shooting from it's inception into the NCAA. Once coaches started to figure out that it was affecting the outcome of the games, they decided they should probably figure out how to defend against it.

in me for the correlation of 2pt percentage vs 3pt percentage in the years directly after the inception of the 3pt shot. Not that it directly relates to the original post... just would be neat to see how the overall percentages were affected by the inception and resulting defensive adjustments. Also, do these trends follow other rule changes in the game? I'm sure that I'm overanalyzing, but my daddy always told me to stick with what I'm good at...

I have for years theorized that the overwhelming popularity of Michael Jordan has as much to do with the dribble drive overtaking the open shot, as the most practiced play in basketball.

Very interesting timeline information, though. Jordan's popularity exploded in the US around the time that the shooting percentages began to drop, which is also roughly the same time that the 3-point shot was introduced. A confluence of separate forces which conspired to rob us of great shooters. Works for me.

Great shooters open up so much offensively for their teams, which only improves all offensive statistics. UT, last year, struggled mightily when Lofton was hurt. Lending credence to the theory that great players make good players, very good.

Jared Prickett's freshman year at UK was his best, as far as scoring average is concerned. Prickett's sophomore year, after Mashburn left, his scoring dropped dramatically, because defenses keyed on him without worry of Mashburn dropping a three, or driving his elbow through the basket as he posterized them.

Point being: Great shooters, and sometimes great scorers, help raise the shooting percentages of their teammates. Without as many great shooters, teams, overall, do not shoot as good of a percentage. Which of course adversely impacts the graphs that Tru posted, and expertly analyzed.

I must agree with just about everyone else who has posted on the subject. More than likely a combination of all posted theories are responsible for the declne in overall shooting percentages in the college game.

Personnally, I think Dale Brown is shortchanged by the national media. The impact his game-changing "freak' defense had on the college game is immeasurable. It altered college ball forever. Oh, where have you gone Dale?

Fun, fun, fun....I couldn't resist this one.  Interesting numbers -- thanks for posting them.  I have a theory.  Instead of talking about shooting percentage, why not talk about "expected points?"  Shooting percentage, in a way, is meaningless if different shots have different point values.  If you can get more points by taking a lower percentage shot, then you cannot assert that lower shooting percentages are necessarily bad.  What is bad is if you are not getting points!  
So, let's say
A) the average expected points from a 2-point field goal = 2 * (2pt f.g. percentage)
B) the average expected points from a 3-point field goal = 3 * (3pt f.g. percentage)

Given that assumption, then at its peak (1981) the 2 point attempt was worth 0.96 expected points per shot.  In 1987, it looks from the graph like it was worth approx. 0.93 expected points.  Meanwhile, the new 3-pointer was worth 3*0.384=1.15 expected points.

Based on this, then clearly it is better to shoot three pointers in 1987.  So, my theory says, teams learn this, adjust, and take more and more 3-pointers (using worse shot selection & worse shooters) up until the point that the 3-point shot is worth no more than a two point shot.

So, 3-point attempts continue to rise, and 3-point field goal percentage continues to decline, as shown in the graph, until the percentage is approximately 33% or 1/3, and the expected value of the 3-point shot is exactly 1.0 points, much closer to the approximately 0.88 (as of now) expected points of the 2 point shot.

So this theory explains, I think, why teams keep shooting more and more 3 pointers, even as three point percentage continues to decline, and would suggest that this trend will continue as long as the expected point value is higher than for the 2 point attempt.  However, the data seem to indicate otherwise -- that it has leveled off.  

I suspect this is because of the factors that have been left out of my simple assumptions.  For example, other factors, like making more free throws -- including 3-point plays -- if you take it inside, would perhaps increase the expected point value of a 2-point shot attempt.  Also, non-point factors would be valuable, such as causing opponent players to foul out by taking more shots in the paint.  If this is true, then we would expect it to level out before the two values converge completely, as it seems to have done.

This theory does not explain the simultaneous decline in two point field goal percentage, though.  And it certainly does not address the effects of recruiting 3-point shooters and all of that.

Tru, did you get your numbers from the NCAA's all-time trend document (http://www.ncaa.org/stats/m_basketball/trends/all_time_trends.pdf). It looks like you did based on your graphs. The NCAA has done a poor job of not separately tracking 2-point shooting percentage apart from overall shooting percentage. When you mention numbers like 43.5% in 2000, this refers to the aggregate of 2-point and 3-point shooting. These FG% numbers do not indicate a decline in 2-point shooting as the NCAA has not separately tracked it. Overall FG% has declined because of 3-point shooting as you would expect. Only now are we seeing people like Ken Pomeroy (http://kenpom.com) track the 2-point shooting separate from overall FG%. Last year, UK shoot 54% from 2s and 35% from 3s (http://kenpom.com/sr.php?team=Kentucky).

Most of this can be addressed to the advent of the 3-point shot.  Even mediocre shooters take too many shots behing the 3-point line.

And you don't see as many players driving to the basket as much as they used to.

Actually your very best and wide open 3-point shots originate from a player driving to the basket and kicking it back out to a wide open shooter.

Instead most shooters nowadays just stand beyond the 3-point line and jack it up no matter if they're wide open or not.

Today's game is outside-in.  Back in the older days it was inside-out.

The best teams in college basketball today almost always have the inside-out philosophy instead of the outside-in strategy most schools applied in the older days.

That to me is the main reason shooting has declined over the years.

The best teams in college basketball today adhere to the inside-out philosophy instead of the outside-in philosophy.  I misquoted myself in the next to last paragraph.

Sorry for the misuderstanding.