Did the surge work in Iraq?

Statistically and operationally speaking yes? The biggest failure (in my lonely opinion) from the start of the war in Iraq is that we went in "in the middle" with regards to our capabilities and strength. What I mean is, we should have went in light (SOF forces only, over an extended period) or super heavy (surge-like numbers). We went inbetween.

However, when you commit to occupy, you need to occupy. We needed the SOFA to extend and we needed to set up camp. Iraq could have turned into an oversees tour like Korea...over time.

Now, it seems we are starting from scratch with a slight advantage of learning from our past mistakes.

Yes! At the time, it worked. But our hasty departure made it all a huge waste of time and men/women....

Did the surge work? For a time, the increased presence may have made enemy C3 more difficult. However whether it did more good than harm? That is hard to say, and I'd argue dependent on region. Were the gains sustainable? In the long-term, no. Just as with every other tactic, the enemy adapts. Successful COIN is more difficult than just throwing more and more troops at the problem.