The journalist's fallacy is the name I gave to the habit of drawing strong inferences from only one or two data-points. We've seen two nice examples of it this week, from left and right.

From the left, we have Seamus Milne. He points to Manchester University students who are campaigning for a more pluralistic economics curriculum as a sign that "orthodox economist have failed their own market test. Granted, he could have widened the evidence base; there's a similar movement at Cambridge, at least. But he omits two facts:

- Demand to study ("orthodox") economics at university has risen 33% in the last six years, whilst applications to university generally are up by only 19%.

- At least two universities - Oxford and Manchester; I know coz I took 'em - used to offer courses in the history of economic thought, but dropped them in part for lack of demand.

These two facts suggest that demand for "orthodox" economics is strong. It's too damned strong in my book, but things are as they are, not as we'd like them to be. (And anyway, the truth or not of "orthodox" economics is not to be decided by what undergraduates think.)

From the right, we have Melanie Phillips' attempt to tell us that the Paul Flowers affair tells us something about the broader liberal-left. But she doesn't point that many Labour and Coop members are not financially illiterate drug-takers, nor that - perhaps! - some on the right might be. She doesn't even try to fill in the Bayesian boxes. Granted, she might have cited Hayek's "Why the worst get on top", but that could apply - as he says - to "any society."

There are thousands of coops in the UK, and only one (or a few) Paul Flowers. The question - which is of fundamental importance - is: are coops more efficient than capitalistic firms? This cannot be settled merely by pointing to any individual personal failure, but by wider statistical research.

Seamus and Melanie are committing a similar error. Both are inferring too much from individual examples - an error exacerbated by wishful thinking. They are neglecting the very useful advice offered in this great piece in nature - that "data can be dredged or cherry picked."

Now, you might object here that pointing out that Seamus and Melanie have limited powers of ratiocination is the epitome of lazy blogging. It is, but there's a more general point here. It's that Seamus and Melanie have successful journalistic careers whereas I don't. One reason (of several!) for this is that the lively human interest anecdote is more vivid and interesting than dull statistics; admit it, you'd rather read about Flowers' porn habit than about the relative productivity of worker- versus capitalist-owned firms. And journalism is about giving readers what they want, not about high-minded logic and evidence.

All of which makes me suspect that Noah Smith might have added something here.