In 1985, Joel Best published an article
in the sociology journal Social Problems
analyzing reports of children receiving dangerous treats on Halloween (razor blades in apples, poisoned candy, etc.).
After doing an extensive review of newspaper databases for all cases between 1959 and 1984, he couldn't find a single instance of a child being killed by a Halloween treat, although there were a handful of cases (18) of minor injuries, and a larger number of reports of the discovery of contaminated treats without injury. Although he suspected that most if not all of these discovery reports were hoaxes.
So he concluded that the idea of "Halloween Sadism" was an urban legend that emerged into national prominence during the early 1970s because of fears about the safety of children:
The Halloween sadist has become an annual reminder of the fragility of the social bond — an expression of growing doubts about the safety of children, the trustworthiness of strangers, and the strength of the modern urban community.
In an article recently posted on the website of the University of Delaware
(where he teaches) Best looks back on that article and notes that ever since its publication he's been the go-to guy for reporters writing about Halloween safety:
Every October since 1985, I've continued to get calls from reporters. Usually, it's a young person working for a newspaper who's been assigned to write a piece about Halloween safety. There's a pretty good chance that a reporter who goes online to review last year's stories about the topic will see me quoted, so I get called and re-interviewed.
Because of the ongoing interest in this mostly non-existent problem, Best has continued to scan newspapers
for reports of Halloween injuries, and he says that "I still haven't found a documented case of a child who was seriously harmed by a contaminated treat."
Though he notes that this shouldn't be taken to mean that Halloween isn't a potentially dangerous holiday. It is. But for another reason altogether. On Halloween the risk of a child being struck by a car is four times higher than on other nights.