Tuesday, June 21, 2011

More magic numbers


I was alerted to some interesting work by a recent report in the IoP's Physics World magazine. Researchers have finally worked out that there is, in fact, a correlation between group size and quality of research.
The paper (available on arxiv and published in Scientometrics, which is apparently the research of... research) took information from a survey of UK universities (and a few French) and determined the "quality vs quantity" of the research output (the "quality" metric is described in more detail in the paper, but it is essentially the same metric used to determine how much federal funding the researcher gets). This was parameterized (fit mathematically) via a complex system model and something unusual popped out: the model predicted so-called "magic numbers" - at which a research group gets the best return on investment, so to speak. Above this magic number, or critical mass (if you prefer), the group begins to fragment, as is demonstrated in Figure 2 of the paper:

A table of all of the different scientific research areas and the model's predicted "magic number" for that subject is shown below:

Pure mathematics has the lowest magic number (less than 2, a traditionally "every man for himself" kind of field), and one sub-branch of computer science the largest (almost 25, with "business and management" a close second at 24).
Everyone knows anecdotally that, though a trend doesn't necessarily indicate ubiquity, it is true that at a certain point, when a group gets too large, not everyone in the group will be carrying weight and the quality of the research done (per person) goes down. It's fascinating to see this generalization plotted and put to a statistical analysis. As one of the study's authors remarked, he would consider using these results in putting together a research department from scratch.
And, of course, I'd say our group (my last paper had 15 coauthors) is just the right size.


Kenna, R., & Berche, B. (2010). Critical mass and the dependency of research quality on group size Scientometrics, 86 (2), 527-540 DOI: 10.1007/s11192-010-0282-9

Sunday, June 12, 2011

The end of the world

With the rapture come and gone, and the rest of us still here, I find myself in (as physicists would say) a superposition of states: I am simultaneously experiencing fatigue and panic. Yep, the phobia's kicked in. I leave tomorrow morning.
Around the house are signs of the impending apocalypse... the cat sits sulkily in my suitcase and refuses to move, the bottle of diet Mountain Dew has run out, my summer vacation is officially booked (wouldn't the fates just love to steal that from me?), the calendar reminds me that this flight is an anniversary of another... there are signs and wonders everywhere, and Harold Camping isn't the only one who can see them.
The trick is, of course, that I know the things I perceive are only in my head.
But like Sir Frazer knew, things in your head can kill you just as well as can "real" things. The hypertension, the shallow breathing, the teeth-grating, the rush of chemicals - in short, the stress of a phobia - can kill you. The reaction is more dangerous than the trigger, as was the case with the "Spanish flu" epidemic of WWI. So what good is it to "face one's fears" when doing so is, physiologically, bad for you?
In any case, it's all just rambling. There's nothing I can do at this point except take a deep breath and a lorezipam.
Here's hoping that you'll hear from me again tomorrow.