yardstick

noun

1. A measuring rod thirty-six inches (one yard) long.
2. (figuratively)A standard to which other measurements or comparisons are judged.

   “2008 April 8, Michael R. Gordon and Eric Schmitt, “Attacks in Baghdad spiked in March, U.S. data show”, in International Herald Tribune, 2008 April 8 edition, “Africa & Middle East” section, Attacks against civilians in the capital remained relatively unchanged: 69 in March from 62 in February. ¶ However, another yardstick, the number of civilian deaths tracked by the Iraqi government, shot up last month after several months of decline.”