Michael wrote: << How do people feel about this construction, in which you use the phrase "five times less" to colloquially mean what a formal description would have to call "one fifth as much" or the like? This came up on a blog I read, in which commenters seemed about equally divided between "This is just fine, it's completely obvious what the construction means" and "that's literally meaningless, no reasonable person should produce such a statement." At the time I wondered what the breakdown would be among a mathematician audience, and this seems like a chance to find out.

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I feel this is just fine in colloquial writing, and not at all good in a formal report (e.g., a newspaper article). This is because newspaper articles et al. are well known for royally screwing up clarity in such matters. (They will commonly use a phrase like "150% more" whether they mean 3/2 as much or half again as much.) (Michael: This wasn't by any chance Mark Liberman's Language Log", < http://itre.cis.upenn.edu/~myl/languagelog/ >, was it?) --Dan