Virginia Tech Shootings and Hindsight Bias

Megan McArdle, guesting at Andrew Sullivan’s place, argues that the initial reaction to yesterday’s Virginia Tech massacre may be clouded by hindsight bias.

[E]ven if all mass-murderers did write scary prose, or make sweeping apocalyptic statements, or otherwise give some signal of their impending meltdown, the signal wouldn’t do us any good, because mass murderers are really, really rare. You’ll have a thousand false positives for one false negative. In hindsight, we can always pick out some clue to what was about to happen. That doesn’t mean that we can, or should, see those things beforehand.

Related is the criticism of administrators for sending students to class after the first murder, or of police for not locking the campus down immediately. This is a classic problem with recriminations: we tend to assume that the fact we had a bad outcome means we made a bad decision. But in an uncertain world, this is ludicrous. Good decision making concentrates on the most likely events, not the wild outliers.

The errors of a false negative (what social scientists call “Type II errors”) can be quite catastrophic. Had Virginia Tech officials sounded the warning bells the instant they knew of the first shootings, they may well have saved thirty innocent lives. Similarly, had everyone who had the slightest suspicion that Cho Seung Hui was emotionally unstable brought that to the attention of the proper authorities, thirty two innocent lives may have been saved.

As Megan suggests, however, the consequences of overreaction to the innumerable false positives (“Type I errors”) would be far more debilitating. Witness, for example, the millions of man hours wasted each year providing the illusion of security at the airports.

Do we want every odd teenager turned in to The Powers That Be for certification that he’s not a potential serial killer? Given what we know of bureaucracy, we can rest assured that a whole lot of people would be unnecessarily locked away in order to ensure that false negatives don’t occur. (Which is why it’s unlikely we’ll ever see a terror alert level below Yellow unless the system is scrapped.)

Several years ago, during the first year Steven Taylor and I were teaching at Troy State, a young student was driving recklessly in a severe rainstorm and was killed. Following that tragedy, university officials decided that they would shut down the university during heavy rain storms and, on occasion, even the forecast of same. Worse, if it was raining at all, the policy was to allow students an excused absence at their discretion if they did not feel safe driving. This applied, incidentally, even if the student lived on campus and was walking to class. There’s no way of knowing if this policy saved any lives. It did, however, deprive students of thousands of hours in the classroom for which they had paid.

Human lives are precious and people in leadership positions have a responsibility to ensure the safety of people under their care. But let’s not pretend that safety doesn’t come at a price. Protecting ourselves against infinitesimal risks may make us feel better but it almost certainly senseless.

UPDATE: I should add that I’m not arguing that the officials at Va Tech acted properly, just that we shouldn’t come to the knee-jerk reaction that they screwed up just because something bad happened. My inclination is that they should have notified the campus that shootings had occurred and perhaps even canceled classes while someone was on the loose. Still, they may well have been justified in thinking it was a murder-suicide situation. We simply don’t know at this point.

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James Joyner
About James Joyner
James Joyner is Professor and Department Head of Security Studies at Marine Corps University's Command and Staff College. He's a former Army officer and Desert Storm veteran. Views expressed here are his own. Follow James on Twitter @DrJJoyner.


  1. laura says:

    I think that one of the student’s professors did make some kind of referral to a counselor for the student.

    I’m not disagreeing with the point of your post. Just sayin’.

  2. anjin-san says:

    There was a bomb threat at the local JC a while back and they totally shut the campus down. Better to be safe then sorry.

  3. just me says:

    While I agree that you can’t accuse every loner that writes creepy or off the norm stuff, I am not so sure I agree that the campus shouldn’t have been shut down, or at least students notified that there was a gunman on campus that hadn’t been aprehended yet.

    I think that is where your rainstorm comparison falls short. A rain storm is a normal occurance, a gunman shooting and killing people in a dorm is not.

    I think what bothers me about this situation is that two people were killed at just after 7 in the morning, and the person that killed them was at large. I think students and staff should have been at the very least notified and given the option to decide whether they wanted to come on campus-there was time to do this and yes it may have been disruptive for that day, but it may have prevented some of what happened.

    I don’t think tragedies like this are really all that preventable, I don’t think they make a good springboard to create any policy from, but I do think continueing with school that day was a mistake.

  4. Herb Ely says:

    After an auto accident my insurance agent told me an old Virginia proverb: “Hindsight is better than foresight by a damn sight.”

  5. tom says:

    Every time there is a murder in NYC (or any city), the mayor should play it safe and shut the city down until the suspect is apprehended. You never know, a murder on the lose could walk in to a shopping mail and open up. Better safe than sorry!

  6. Bithead says:

    the question is, would it have made any difference, in the end?

    I doubt it.

    The actions of officials we don’t know fully, yet… and we won’t for a while, as the investigation unfolds. But in the end they do not matter all that much…. regardless of what they did, campus officials simply are not equipped to deal with such conditions, due as much to their own gun phobia as political correctness and gun control laws.

    The large numbers of people, and the lack of instant communication ability with everyone on campus, renders anything the president of VT did or did not do, nigh on insignificant. How do you empty a campus in time to do anything about such an event?

  7. anjin-san says:


    Maybe they were not up to dealing with it because they were not up to dealing with it, but I am sure you will get around to blaming Clinton soon…

  8. Bithead says:

    Clinton, particularly?

    Just gun controlers in general.

  9. just me says:

    Bithead-the initial shooting occurred before most classes started, if VT is anything like my college, classes started at 8 with few exceptions.

    Every time there is a murder in NYC (or any city), the mayor should play it safe and shut the city down until the suspect is apprehended. You never know, a murder on the lose could walk in to a shopping mail and open up. Better safe than sorry!

    Not the same thing. And I know that police have at times notified the community when there is some kind of dangerous person at large.

    I don’t know that shutting down the whole school was in order, but at the very least I think people coming on the campus had the right to know that a gunman had killed two people that morning and the police didn’t know who or where he was. In the end it would have been better to have tried to do something, rather than assume safety.

  10. anjin-san says:

    I am still having a hard time seeing how gun control has anything to do with this tragedy. Seems like using the deaths of so many young people as an excuse to try and score a political point is pretty crappy.

  11. Bithead says:

    The point is simply this;

    All it would have taken would be one… ONE legal firearm, and the perp would have gotten one, perhaps two shots off, and that would have been the end of it… and 30-some-odd less people would have died.

    That’s not a political point, except perhaps by extension. What I’m making here is a point of saving LIVES.