Gary Rubinstein has a serious problem about people who use data to fib.

He just saw a newspaper article about a KIPP school in New York City where “96%” of the graduates were going to college. This seemed improbable so he did some digging, and of course it wasn’t true.

He writes:

One of the dirtiest tricks played by charter schools is when they claim to have a 100% graduation rate and a 100% college acceptance rate. The first use of this, to my knowledge, was when YES Prep used it to help secure $1 million from Oprah. Over the years, it is very common to see some charter school tout a similar statistic.

When I hear about one of these 100% schools, the first thing I ask is “Is this 100% of the starting cohort, or just the senior class?” It is always just the senior class. Then I ask “How many students are in the senior class?” When the number of graduating seniors is in the 30s, 20s, or even most recently in the case of Success Academy, 16, I ask “How big was the initial cohort?”

In The New York Post the other day, there was an article titled “Bronx charter school sending 96 percent of grads to college.” The school was the one KIPP high school in New York City. According to the article, there were 225 graduating seniors, which, at least, is much bigger than the graduating class of many of these 100% (or 96% in this case) stories.

But 96% of the graduating seniors is not 96% of the original cohort and The Post addresses this by saying “The network said 86 percent of the original freshman class stayed on through their senior year.”

The problem with this statistic is that KIPP is a 5th to 12th grade program, not a 9th to 12th grade program.

So the question is, what percent of the original fifth grade class remained to graduate? Not 96%. Not 86%. Read on.

Why must every statistic be inflated?