Claude Werner put together an analysis of NRA Armed Citizen reports and came up with the following:
http://thinkinggunfighter.blogspot.com/2012/03/self-defense-findings.html

The Armed Citizen – A Five Year Analysis

For the period 1997 – 2001, reports of 482 incidents were examined. All involved the use of firearms by private citizens in self defense or defense of others. No law enforcement related incidents were included.

The majority of incidents (52%) took place in the home. Next most common locale (32%) was in a business. Incidents took place in public places in 9% of reports and 7% occurred in or around vehicles. The most common initial crimes were armed robbery (32%), home invasion (30%), and burglary (18%).

Overall, shots were fired by the defender in 72% of incidents. The average and median number of shots fired was 2. When more than 2 shots were fired, it generally appeared that the defender’s initial response was to fire until empty.

Handguns were used in 78% of incidents while long guns were used in 13%; in the balance the type of firearm was not reported. The most common size of handgun was the .35 caliber family (.38, .357, 9mm) at 61%, with most .38s apparently being of the 5 shot variety. Mouseguns (.380s and below) were at 23%, and .40 caliber and up at 15%.

The range of most incidents appears to be short but in excess of touching distance. It appears that most defenders will make the shoot decision shortly before the criminal comes within arm’s length. Defenders frequently communicate with their attackers before shooting.

The firearm was carried on the body of the defender in only 20% of incidents. In 80% of cases, the firearm was obtained from a place of storage, frequently in another room.
Reloading was required in only 3 incidents. One of those involved killing an escaped lion with a .32 caliber revolver, which was eventually successful after 13 shots.
Multiple conspirators were involved in 36% of the incidents. However, there are no apparent cases of drivers or lookouts acting as reinforcements for the criminal actor(s) once shooting starts. Immediate flight is the most common response for drivers and lookouts at the sound of gunfire.

The largest group of violent criminal actors was 7, who committed serial home invasions in Rochester NY. An alert and prepared homeowner dispatched them (2 killed and 1 seriously wounded) with a shotgun when they broke in his door.

Incidents rarely occurred in reaction time (i.e., ¼ second increments). Most commonly, criminals acted in a shark-like fashion, slowly circling and alerting their intended victims. The defender(s) then had time to access even weapons that were stored in other rooms and bring them to bear.

The most common responses of criminals upon being shot were to flee immediately or expire. With few exceptions, criminals ceased their advances immediately upon being shot. Even mouseguns displayed a significant degree of immediate lethality (30% immediate one shot kills) when employed at close range. Many criminal actors vocally expressed their fear of being shot when the defender displayed a weapon. Upon the criminals’ flight, the “victims” frequently chased and captured or shot the criminals and held them for the authorities.

Karl Rehn, an Austin-based shooting and CCW instructor and high level competition shooter added:

The Armed Citizen data doesn’t agree with the data that Tom Givens presents, on the 56 shootings his students have been involved in. Distances are 5 yards or less, but total rounds fired ranged from 1-11.

If you take the analysis literally, it encourages people NOT to carry, since it shows that they are at little risk outside the home, which is BS. Most of Givens’ student-involved shootings occurred outside the home. There were 1130 carjackings in Houston last year. Violent crime in downtown Austin, Texas is up 83% – that’s all ‘outside the home’ down in the tourist area.

If 2 rounds is the “average” number, so what? Training to the average means that 50% of the time you will come up short. What’s much more important is the 90% level – how many total rounds were fired in 90% of the incidents in which the armed citizen prevailed?

The vast majority of people involved in “Armed Citizen” incidents are untrained, so using the analysis as a roadmap for what we “should do” is flawed thinking — like the people that tell us we shouldn’t use the sights because untrained people, under stress, don’t use their sights.

The high number of self-inflicted gunshot wounds shows a need for better training, particularly in safe gun handling. Long heavy trigger pulls make a gun idiotproof but also make it harder to shoot. I’ve been training students for 20+ years and haven’t had any students shoot themselves. Again, the actions of the untrained should not define best practices for the skilled.

To borrow a phrase from brokers and investment firms: Past performance is not an indicator of future performance. It is useful to look into such collected data for clues but following the path of largely novice-level masses is not your only choice.