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.
If you use someone or something as a yardstick, you use them as a standard for comparison when you are judging other people or things. There has been no yardstick by which potential students can assess individual schools before signing up for a course