The Collaborative International Dictionary of English v.0.48:

Yardstick \Yard"stick`\ (y[aum]rd"st[i^]k`), n.
   A stick three feet, or a yard, in length, used as a measure
   of distance, cloth, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

yardstick
    n 1: a measure or standard used for comparison; "on what kind of
         yardstick is he basing his judgment?"
    2: a ruler or tape that is three feet long [syn: yardstick,
       yard measure]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "yardstick":
   barometer, basis, benchmark, canon, check, criterion, degree,
   exemplar, gauge, graduated scale, measure, model, norm, parameter,
   pattern, quantity, reading, readout, rule, scale, standard, test,
   touchstone, type, value