typically, the DA would not press charges if it was an obvious self-defense case, or accidental. and obviously if the shooter was dead, or it was a suicide, there wouldn't be anyone left to charge, so the case would just be a police record.
if it wasn't clear, and they were charged and not convicted, there wouldn't be a ruling on whether it was self-defense or not... the jury would acquit.
here's what the study says. seems more or less clear to me that most of these incidents are as they say they are, and there's not like 100's of self-defense cases up in the air, as spartanhack/racist alleges:
In 84 percent of the incidents (455) the concealed carry killer committed suicide (218), has already been convicted (177), perpetrated a murder-suicide (44), or was killed in the incident (16). Of the 69 cases still pending, the vast majority (60) of concealed carry killers have been charged with criminal homicide, four were deemed incompetent to stand trial, and five incidents are still under investigation. An additional 20 incidents were fatal unintentional shootings involving the gun of the concealed handgun permit holder.