The 30/70 Rule or the 70/30 Rule

The 30/70 Rule or the 70/30 Rule

In an article published on The Learning Counsel, Betsy Hill and Roger Stark write …

Businesses often refer to the 80/20 rule.  When they do, it is in this context: 80 percent of our sales come from 20 percent of our customers. Or 20 percent of our customers account for 80 percent of our customer service issues. Almost any organization can probably come up with an 80/20 rule.

In education, we have been struck by a similar pattern and are starting to think that there may be a 70/30 rule in operation. Here are some proportions for consideration.

Students who perform at the 70^th percentile on cognitive ability tests such as the CogAT (the CCAT in Canada) are very likely to learn and perform at “grade level” without adjustments to the curriculum or instruction. That corresponds to 30 percent of the student population.

The percentage of students performing at grade level in the U.S. is about 37 percent in reading at the 4^th grade and about 40 percent in math at the fourth grade. The percentages decline and are closer to 30 percent at 8^th grade. And that is about the percentage of students one would expect to be performing at grade level, given standard instruction and curriculum and typical performance on cognitive assessments.

Perhaps we should call it the 30/70 rule.

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