On Sun, 24 Feb 2008 14:45:58 -0800 (PST), Andrew Sarangan
wrote in
:

Anyone know what makes them so notoriously inaccurate?

A lack of federal regulations mandating their accuracy throughout
their range? :-)

Perhaps inaccuracy is induced over time, because of drift of the
resistance element. But I'd sooner believe, it's because there is no
regulation for accuracy.