There was a study done recently in your area that might offer you the kind of information you are looking for. A group of researchers from the University of Wisconsin (Madison) enrolled 1460 high school athletes in a study designed to determine the effect of lace-up ankle braces on injury rates in athletes.
This may be the first study to look at preventing ankle sprains (and other leg injuries) by wearing a soft, lace-up ankle brace. All participants were basketball players. The study included males and females involved in high school basketball during the 2009-2010 season.
The athletes were randomly divided into two groups. One group received the ankle brace. The other group was the control group (no brace). Athletes in the brace group wore the McDavid Ultralight 195 brace during any conditioning session, practice, or game throughout the season. This particular brace was chosen because it happens to be one that is used by many high school and college-level athletes.
As you might expect, the braced group did have fewer injuries. But the brace did not reduce the severity of the ankle injuries. Bracing did not prevent knee injuries either. The number of acute knee injuries was similar between the two groups.
What do the results of this large study really tell us? Wearing a lace-up ankle brace is effective in reducing ankle injuries in high school basketball players regardless of age, sex (male or female), or body mass index (body weight for size). The protective effect of this simple device also helps athletes who have already had a previous ankle injury from reinjuring that ankle again. This is good news since ankle reinjury is a common problem in athletes.
There are plenty of other factors to consider when trying to reduce the number of ankle injuries. Type of shoes (low-, mid-, or high-top) may make a difference. Player compliance in wearing a brace could be a key factor. The role of neuromuscular training has also been explored by other researchers and should not be ignored. But it looks like you have taken on an important problem and started with an approach that has some evidence to support it.