T. Mark Gibson writes:

As the saying goes, “If it saves only one life…”

I think that something like 1/6th of people who use guns in defense
believe that they saved an innocent life by doing so. So even if we
were to accept the gross underestimate of the number of times people
use guns in self-defense, we could still be talking about over 13,000
lives saved each year by armed citizens.

Except that 16% of violent crimes do not result in the victim’s death.
In fact, only 0.35% of assaults result in death (Kleck table 5.8).
0.35%*80,000=300 lives saved with guns each year. This is an
overestimate since it assumes that guns are 100% effective and that
all of the 80,000 crimes that guns were used to defend against were
assaults when in fact some were robberies and burglaries (which have
lower fatality rates than assaults). Correcting for these would give
an estimate of more like 200.

The NCS undercounts crimes like domestic assault, so the 80,000 could
be too low, possibly even by a factor of two. This possibility does
not affect the estimate above, since the undercounting will cause a
compensating overestimate in the lethality of assaults.

If we accept the well-supported
estimate of 1,000,000 incidents where citizens use guns to protect
themselves each year, we could be talking about almost 170,000 lives
saved.

If this 1M estimate is true we cannot estimate the number of lives
saved since we do not have enough knowledge of the nature of the
incident to estimate the chance of death.

If Kleck’s latest results are are correct, and there are over
2.4 million incidents where people use guns defensively each year,
there could be as many as 400,000 lives saved.

Reductio ad absurdum. Since 400,000 lives saved is a ridiculous
number (roughly half of US households have guns — how come there
aren’t 400,000 dead bodies amongst the half of the population with no
gun access?) you have proved that some significant number of Kleck’s
respondents did not tell the truth. Congratulations, Mark, I knew you
had it in you.

If only 10% of the people
who think they saved an innocent life were actually correct and we
use Kleck’s latest estimate, it still leaves about 40,000 lives saved
by armed citizens each year.

Which is also impossible.