...unless we know the population size -- in the statistical sense, where "population" means "the whole set of entities of the kind studied; the set about which conclusions are to be drawn" -- i.e, in this case, "important" (or "prominent") microbiologists, at some not-very-rigorously-specified "top level".

From the article:

"Statistically, what are the chances?" wondered a prominent North American microbiologist reached last night at an international meeting of infectious-disease specialists in Chicago.

Janet Shoemaker, director of public and scientific affairs of the American Society for Microbiology in Washington, D.C., pointed out yesterday that there are about 20,000 academic researchers in microbiology in the U.S. Still, not all of these are of the elevated calibre of those recently deceased.

Yeah, well, how do you measure just how "elevated calibre" these guys were? Was the "lowest-ranked" of them at, say, position 1,000 of all the 20,000? Or position 500? Or position 5,000? (Let's see the academic squabbles *that* attempt at generating a comprehensive top-to-bottom listing of relative "elevated calibre" among all U.S. academic researchers in microbiology will generate... ;^)

So we can really only speculate here... OK, here goes:

Now, say the least-"prominent" of these guys was actually only #10,000 on the "objective" list of "importance". That would mean eleven guys out of 10,000 died a "violent" (apparently a mixture of suicides, homicides, industrial accidents, and not-clear-which-of-those) death in six months... So -- isn't that, if anything, *below* average? As a European, one gets the impression a significant percentage (something in the region of three to ten percent) of the American population is slain by its compatriots each year...

You'd have to show me some comparative "violent"-mortality statistic for the general population to convince me this is anything out of the ordinary, in the first place.

Furthermore, you have the vagrancies of probability, taking into account and compensating for which the science of statistical sampling is all about: Even if the "lowest-ranked" of these ex-("He's just pining for the fjords!")researchers were at so elevated a position as, say, #1,000 on the "ranking list", how would we know this meant that "Eleven of the top 1,000 microbiologists died!"? It could, in fact, just as well be that the actual case was, "Eleven of the top 1,300 microbiologists died!" -- maybe a sub-population consisting of the top 1,x00 guys have something else, completely non-sinister, in common that singles them out from the main body? -- and random chance has seen to it that the lowest-ranked of the eleven that actually *did* die, during this specific sampling period, *happened* to be at #1,000 of those 1,300 (as well as of the whole 20,000).

You'd have to do some pretty extensive cluster and factor analysis to convince me something like that couldn't be the case -- only *then* could we start discussing whether eleven out of 1,x00 (or 2,x00, or 3,x00...?) is all that remarkable a percentage.

Lastly, the whole population figure mz Shoemaker supplies (cf "there are about 20,000 academic researchers in microbiology in the U.S.", above) -- is totally bogus! Apart from all the Russian defectors, in the US and the UK, that are included in the "Eleven Violent Deaths!" figure, you have:

• two guys with British-sounding names, who died in Britain;
• one Russian non-defector, who died in Russia;
• a guy with a very Vietnamese-sounding name, who died in Australia;
• the chap in San Francisco, who offed himself after killing the Russian chick (with the German-sounding name; Jewish, perhaps) -- his name sounds Chinese;
• the first to go, a mr Benito Que -- a very Hispanic-sounding, or perhaps most of all, Philippines-style, name; was he an "American" researcher or a foreigner *doing research IN* America?
  

So you'd have to add to those "20,000 microbiologists in the U.S", *at least* the number of microbiologists in the U.K and the number of microbiologists in Russia, and probably at least some proportion of the number of microbiologists in Australia, Vietnam, China and possibly the Philippines.

Suddenly, eleven deaths in six months doesn't really look like that many at all, does it?