I'm downvoting this because it's being polemic without reason. Mother Jones gives a precise definition of what they consider a mass shooting: "Our research has focused on seemingly indiscriminate rampages in public places resulting in four or more victims killed." - whether we agree or not with this is irrelevant and not needed to answer the question.

I don't have any problem with motherjones writing their own article about seemingly indiscriminate rampages in public places but condensed down to a little graph I believe it's potentially misleading once stripped of that context. What data you include in the catagory of "mass shootings" is quite relevant to a question about mass shootings.

Is the mother jones list incomplete according to their definition? You haven't shown that.

I'm not claiming that the motherjones article is incomplete according to their definition but the definition of "seemingly indiscriminate rampages in public places" goes quite a bit beyond simple mass shootings which can reasonably include things like driveby gangland shootings which are neither random nor indiscriminate . Hence the link provided to the larger list of mass-shootings. You're demanding evidence for things I've not claimed.

That's what the question is asking though, and your answer states "The problem is that this is a very very very incomplete list". I am not sure how else it is going to be interpreted.

@Skliwz This post answered the question as asked, that is until you edited it to no longer read "Do most mass shooters in USA use legally obtained firearms" and instead read "Is this graph of “mass shootings” backed up by reliable data?" Amazingly if you personally edit questions to ask utterly different things some of the answers will no longer apply accurately

@Murphy I edit the questions that would otherwise be closed because they ask for opinions. Please avoid accusing me of stuff. It is unfair.

I only suggested how you could improve your answer, if you disagree, then be it.

If you're going to attack an answer for failing to answer the question it's bad form to first edit the question to make sure it doesn't apply.

or at least mention that you've edited the question

I really have nothing to answer to your insinuations, except that they will get you nowhere fast.

Your answer is bad no matter what I edit. I only changed the title of the question, the body is the same. And your answer is poorly referenced and overly opinionated no matter what the question is.

The question, even in its original form asks "Is this backed by any hard data?"

You haven't examined the data. You just posted a link to a different set of data.

no, it really isn't. Have you actually read my point. I said that it matters how you define what you consider a "mass shooting" and pointed to a dataset with far far more mass shootings included and included an example.

ELI5. How does that answer whether the data in the graph is valid?

also no, you're making false claims. look at the edit history the original question was titled "Do most mass shooters in USA use legally obtained firearms?"

Seriously, don't be a dick. Thank you.

it was a factual question, he could have posted a graph based on 3 randomly selected incidents and it would have been true, hard data but it may not have been representative of all mass shootings in the USA.

How am I being a dick, you keep making false claims and editing things to match them and then pretending everyone else is doing soemthing odd. Pointing out your bad behaviour isn't being a dick. it's failing to let you get away with being one.

You are being a dick because you are accusing me of stuff instead of simply comparing your point of view to mine. I did not attack you. I did not assume intent on your part. I've treated you respectfully. You keep on accusing me of imaginary stuff.

Seriously, I've got better things to do than dealing with people with an axe to grind. If you want to discuss this fairly and calmly, I'm all for it.

Right, if you'll stop shifting the sand under the discussion I'll happily argue facts.

You keep on doing that.

Talk about what I say, not what you imagine I do

You appear to be talking me saying that a claim of yours is factually false as a personal attack.

I have edited the question because the alternative was closing it. Due to this being a hot topic and due to multiple previous questions that blew up, we are not going to accept questions on skeptics that debate the meaning of "mass murder"

The question was about a specific number, so I focused it on it

The body already asked about the data, I haven't touched it

Regarding your answer: I think it presents poor evidence because the evidence refers to a non overlapping time period.

Also it seems to claim a lot of stuff which is not quite supported by the evidence it presents, for example that the MJ data is missing data points.

I added an example datapoint from the larger ShootingTracker dataset. I suspect it would have been excluded from the motherjones data since they're using the pre-2012 definition of 4 fatalities not including the shooter but in more recent times the FBI have included shootings with I think 4 or more injuries not including the shooter.

If you look here: motherjones.com/politics/2012/07/mass-shootings-map

Though I'd need to check that, various articles on it warned that how the FBI treated mass shootings has changed.

you will notice, scrolling donw, that their criteria are a bit more complex and qualitative than one would expect

Which (I think) make their data quantitatively unreliable, but likely more significant in terms of qualitative results

in other words, their dataset contains mostly clear-cut cases giving a specific signal

I agree, though in terms of the initial question about the legality of the firearms used in mass-shootings I believe that the exclusion criteria of "Crimes primarily related to gang activity, armed robbery, or domestic violence in homes are not included." is very likely to exclude a disproportionate amount of illegal weapons.

which makes your example irrelevant, unfortunately (gunviolencearchive.org/incident/150299)

@Murphy i agree, it makes a much more specific & nuanced point than it would appear from the graph.

With the revised question i agree, the example doesn't fit motherjones criteria.

The motherjones dataset appears to be good/correct as far as I can find with their exclusion criteria.

I've removed my downvote, i think your answer is getting better now. Thanks

My initial beef was more with their choice of criteria being then used to support the claim in the graph.

I need to heavily edit the answer to better match the question as it stands.