Girl crushed by tree during teacher strike
http://www.telegraph.co.uk/news/uknews/8610392/13-year-old-girl-crushed-by-tree-during-teacher-strike.html, published 01 Jul 2011, last verified 7/16/2011

Girl crushed to death by a falling branch as she sat on park bench on the day her teachers went out on strike
http://www.dailymail.co.uk/news/article-2010193/Teachers-strike-Sophie-Howard-13-killed-falling-branch-school-closed.html, published 2nd July 2011, last verified 7/16/2011

These headlines are from the UK national newspapers the Daily Mail and Daily Telegraph. Both highlight the fact that the death occurred during a teacher’s strike, which closed the girl’s school. The headlines and the articles themselves imply the claim that:

(1) The teacher’s strike caused the girl’s death.

Indeed, on the following day both articles were criticised in another national newspaper, the i on Saturday, (print edition, p. 20) precisely because they seemed to imply (1).
The informal reasoning behind (1) goes as follows: the strike caused the girl’s school to close; had the school been open, she would not have been in the park and she would not have died; therefore the strike caused the death. This assumes a counterfactual account of causation. A quote from the Daily Mail article nicely illustrates the counterfactual claim that is supposed to entail (1):

(2) “if the teachers were not on strike… [the girl] would have been at school, and this [the death] would not have happened.”

It seems probable that the closure of the school was a necessary condition for the girl being in the park, at the time when the branch fell. Or put another way, it seems probable that the girl’s death (by the falling branch) could only have occurred if the school was closed. Were it open, she would not have died. It is highly probable that this is true; however it is a fallacy to assume that, in general, all necessary conditions for events are causes. Consider the following example:

(3) John passed his driving test.
(4) If John were not human (if he were a dog, say), he would not have passed a driving test.

Certainly being human is a necessary condition for (3). Equally however the fact that John is a human is not considered a cause of him passing the test. There are more proximate factors to consider, such as the hours he spent taking driving lessons. Passing a driving test requires one to be human, but even given that, it requires much more besides. If we want to explain why (3) occurred, then there are the more relevant counterfactual scenarios to consider than (4).
Similarly in the case of the girl’s death there are other factors to consider. More proximate factors include the girl being in the park (as opposed to being elsewhere), and the branching falling at that moment (as opposed to some other). There are a range of counterfactual scenarios in which the school was in fact closed by the strike, but the girl would not have been killed by the branch.
The inference from (2) to (1) is fallacious because the counterfactual scenario in (2) in too remote. Much else could have happened besides to prevent the girl’s death, even though the strike closed the school. To infer (1) from (2) is to neglect these other, more immediately relevant, causal factors.

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The long-running primetime animated series ‘The Simpsons’ demonstrates the fallacy in some kinds of causal reasoning:

From Sears and Sears’ parenting book “The Baby Book: Everything You Need to Know About Your Baby From Birth to Age Two“:

Mark and Kelly were first-time parents who were blessed with a high-need baby—especially at night. They were sensitive and responsive parents, but one day a friend gave them a cry-it-out book, with the admonition, “Now you’ll be tempted to give in, but harden your hearts and in a few nights he’ll sleep.” As their one-year-old baby screamed, these sensitive parents stood sweating and hurting outside his door, afraid to go in and “break the rules.” Each night baby’s night waking decreased, as did the parents’ attachment. Baby cried in a feeling of mistrust and cried the sensitivity right out of the parents. Previously Mark and Kelly had taken baby Matthew with them everywhere because they wanted to and it felt wrong to leave him. Well, it was now easier to leave him. Getaway weekends extended to getaway weeks. A distance developed between parents and baby. More was cried out of the family than only night waking.

A clip from one of the first episodes of ‘The West Wing,’ in which President Barlett explains post hoc ergo propter hoc to his staff that “We didn’t lose Texas because of the hat comment…”