"The preponderance of current evidence indicates that gun availability is a risk factor for youth suicide in the United States. The evidence that gun availability increases the suicide rates of adults is credible, but is currently less compelling."
1) Their gun in self defense studies http://www.hsph.harvard.edu/hicrc/firearms-research/gun-thre... have stats that do not match the US Dept of Justice
2) I would love to get ahold of the full study for #13 "The public does not understand the importance of method availability." because it would explain their base beliefs on a lot of the rest of the page.
Consider a family with a youth who accidentally shot themselves. Rather than state that it was an accident, the family tells authorities that it was a "suicide".
Consider a family with an adult that chooses to commit suicide. Rather than state that it was a suicide, the family tells the authorities that it was an "accident".
Is there a good reason to believe that one of these effects is stronger than the other?
That's a great statistical question! If the data skew was proportionally equal in both directions, the two skews would cancel each other out, right?
Unfortunately, we don't know if the data skews towards accidents, or skews towards suicides, or skews towards them both equally. Here is the snarky one-liner answer to your question:
>>>Is there a good reason to believe that one of these effects is not stronger than the other?