This could and probably should be a fanshot, but there is some really good information, so I am going to make this a worthy fanpost by summing up the two articles based on the work of David Romer a professor at Berkley.
These two articles are fantastic reads, they break down the odds of when and why coaches should go for it on 4th down. I will sum them up after the jump.
Not to get too technical but Romer calculated the expected points for these various situations, then used those expected points to coe up with when a team should go for it and when a team should attempt a kick. He based these numbers after studying every 4th down in the first quarter of a game between 1998 and 2000.
Now I don't want to do this articles based on the work of Romer injustice but I will try and summarize them.
So if a team were to get to their opponents 30 yard line and had a 4th and 3, they have 2 options... Kick the field goal, or go for it. After crunching the numbers Romer calculated that there was a 60% chance of conversion, and teams that converted that 4th down had a 40% chance of scoring a Touchdown. Now Im not sure how expected points is calculated (though I imagine it is based on field position, and how often a team scores from that position on the field), but basically going for it on 4th down from the 30 yard line equals 1.7 expected points. Now Romer also found out that 65% of field goals kicked from the 32 yard line were no good (remember this is actually a 49 yard field goal). So attempting a field goal from the 32 yard line equaled 1.05 expected points. Since 1.7>1.05 if you always go for it on 4th down you will score more points over the long run.
Okay so that last paragraph borders on plagiarism and you can read the original from the first link above it goes on to explain how many more wins this can potentially result in, and the psychology of why coaches do not do this despite the evidence explaining why you should.
The Second article was written by Michael Lewis (the guy who wrote Moneyball and the Blind Side), you may recall that he helped bring attention to the masses about statistical analysis and how the Oakland A's were able to compete with a much smaller budget in the late 90's early 00's.
You may not agree with these articles, but they are definitely good reads, if you think about the 'controversial' failed 4th down attempt against the Jags, if Succop missed the field goal, then the Jags would have had an extra 7 yards to their benefit. I personally do not think Haley is a gambler, I think he is maximizing all the available data, and using it to get a leg up in a very competitive NFL.