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Comment by s1artibartfast | Hacker News Reader

I think you are overstating the predictive power. You can find strong correlations looking backwards, but that doesn't mean that they are good or strong predictors looking forward.

To take just one of your data points as an example, 78% of suicides were preceded by a stressor. If you flip it to make a prediction, what percentage of Life stressors lead to suicide? The number of people who experience major life stressors must be enormous. If tens or hundreds of millions people have major stressors a year, that doesn't help you very much in targeting limited services .

The same holds true for psychiatric care. Prior suicide attempt is probably the exception there, but even that int ~30% predictive power looking foward.

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You're missing that the models (including mental models) that professionals use to predict suicidality are not univariate.

When a manic depressive with substance abuse issues and prior suicide attempts walks into a clinic nobody needs a "new cognitive science tool" to tell them if they're high suicide risk, and these cases are a larger proportion of suicides than most people think.

Also that sort of missed the point of my comment, which is perhaps my fault for not being clear enough. Preventing suicide is a two step process:

1) find high risk people

2) prevent their suicide attempts

My comment was simply relaying the POV of someone who does this professionally: as a society we are better than most people think at #1 and worse than most people think at #2.

I think we still might be talking past each other. My assumption would be that we do a pretty terrible job at both #1 and #2 on your list, and we should look at how we can do both better. I don't think it is a competition.

I have no doubt that professionals can predict suicide for some people with actually high confidence, e.g. >50%. Sometimes it is just obvious to anyone with eyes. My point is that despite this, it doesn't mean that they are good at finding suicidal people in general.

If 45k Americans kill themselves per year, how many of those were previously identified as "high risk". How many total are identified as high risk?

Most of the things we consider as "risk factors" are terrible predictors. Take depression or anxiety, which are considered major factors. They only increase the relative risk of suicide between 2 and 5x. That is crap. When your baseline suicide rate is 13/100,000 and your major depressive is 5X more likely, you are still at 65/100,000.

This is just a long winded way of saying that if you want to claim we are good at predicting suicides, we have to take into account all of the false positives, and all of the false negatives.

If someone gave top professionals the job of predicting which 13 people out of 100k would kill themselves, how many do you think they would get right and how many would they miss?

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