yard·stick 
/ˈjɑɚdˌstɪk/ noun
plural yard·sticks /ˈjɑɚdˌstɪk/ noun [count] 1 : a long, flat tool that is one yard long and is used to measure things 2 : a rule or specific idea about what is acceptable or desirable that is used to judge or measure something
▪ Some feel that test scores aren't an adequate yardstick for judging a student's ability. ▪ Ratings are the yardstick by which TV shows are evaluated by networks.
▪ Some feel that test scores aren't an adequate yardstick for judging a student's ability. ▪ Ratings are the yardstick by which TV shows are evaluated by networks.
