The Next Tenfold Increase in Accuracy of the Electrical Base Units

This decade has seen more than a tenfold improvement towards uncertainties of 0.1 ppm in the realisation, maintenance and dissemination of the ohm, volt and watt. Prospects for a further improvement to 0.01 ppm seem bright if the present level of effort is sustained. This paper is aimed at promoting discussion on the best routes to follow.