Yeah that's David Hemenway, citing himself, funded by an anti-gun group (Joyce), doesn't provide numbers, uses ridiculously tiny sample sizes.
It's really weird that you don't get reliable independent figures when IIRC the federal government is basically banned from collecting most of the useful stats on gun violence and usage. IIRC there was a law/regulation banning the CDC from doing studies into it for 20 years (and such studies tend to take years to do properly).
In other news it's looking like the keystone cops could have done a better job at protecting the students at Robb Elementary school, whilst the school seem to have done everything they could have (they sounded the alarm as soon as they received a warning call, but the murderer was inside the building within a minute of that), the police chief didn't have a radio, the "school resource officer" (aka cop in the school) didn't have keys for the school (unlike standard in many other forces) and the cops were waiting outside the class room door from about 5 minutes after the shootings.
No wonder they're using intimidation tactics on the parents* and press, there is a very very good chance many of those kids would have been alive if they'd followed the procedures put in place something like 20 years earlier, let alone the more rigorous and expanded ones required by Texas law and that they trained for only months earlier, as it's extremely likely some of those poor kids died of blood loss, let alone any shot whilst the officers were stood around.
They waited for something like an hour and it was only the border patrol ignoring the commands of the police chief that put an end to it.
*They threatened one mother with parole violations if she spoke to the press, the Judge basically said "no way" once he/she became aware of that, and praised the woman for doing what the police refused to do (she went in and got her kids out), and have called in biker gangs with links to the police to threaten press who attempt to do their jobs on public ground (I guess it's one way to try and avoid the police force being sued for another failure, as if the police did it directly they'd be facing first amendment lawsuits).