at first, the sierra club grading system compared certain hikes and climbs to others. for example, they might rate climb #3 as harder than climb #1, but easier than climb #2. if a person had never done climbs #1 or #2, this did not help them. to make the system easier to use, the sierra club changed its system. it started to rate hikes and climbs by numbers. this was easier for people to learn and use.