  Electron counting experiments attempt to provide a current of a known number
of electrons per unit time. We propose architectures utilizing a few readily
available electron-pumps or turnstiles with modest error rates of 1 part per
$10^4$ with common sensitive electrometers to achieve the desirable accuracy of
1 part in $10^8$. This is achieved not by counting all transferred electrons
but by counting only the errors of individual devices; these are less frequent
and therefore readily recognized and accounted for. Our proposal thereby eases
the route towards quantum based standards for current and capacitance.
