Markus Kuhn wrote in USMA 20748:
>There seems to be a tradition in the US marketing world, to use
>reciprocal units in order to ensure that a higher number means better. I
>would be curious if you have any reference for where/when this practice
>originated historically.
>
>Fuel consumption, that is volume or mass per distance would be the most
>natural quantity to describe efficiency of a car, but a lower figure
>means better, so its reciprocal value "mileage" was used instead in the
>US.
>
>Similar, for printer resolution, pixel size in micrometers would be the
>technically most natural specification of length, but smaller means
>better, so we ended up with reciprocal length (dots per inch) in the US
>marketing literature. German phototypesetters used to have a resolution
>of 10 �m, these days they are advertised to have 2540 dpi ... :-(
>Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
I think the reason is that the inch is the smallest unit of length in the
imperial system. Lengths shorter than an inch are expressed in halves,
quarters, eigths, 16ths, 32nds, etc. Thousandths ("thous" in Britain,
"mils" in US) are used only by machinists. Hence linear measures less than
an inch tend to be expressed by their reciprocals, thereby avoiding
fractions
Joseph B.Reid
17 Glebe Road West
Toronto M5P 1C8 Tel. 416 486-6071
