The Complicated Cohort Story

I’d like to clarify all of the reporting of data that readers see. There are two ways that we are constantly looking at data–by school year and by cohort.

As a principal, I compare how we did on our Regents exams and graduation rate by school year. That’s what I reported in my earlier post, Winding Down. In addition, we pay attention to the number of student drop outs each school year.

However, the school report card and the Business First rankings look at data by cohort. Data analysis by cohort looks at the students who entered ninth grade together, for example this year’s seniors are largely from the 2003 cohort. What does this mean? That they entered ninth grade together in 2003 and are graduating this year, in four years, in 2007.

How does this get complicated? We pay a lot of attention to our Native American sub-group because we have not had good graduation rate results with this group. Remember that our Native American students add up to about 30% of our population. For example, last year’s cohort, called the 2002 cohort, had only a 48% graduation rate for our Native American students as opposed to 85% for our other students.

That should help readers understand why I pay so much attention to all of our kids. I simply must help more of our students get to a diploma and knowing that half of our Native kids aren’t getting there is unacceptable to me.

This year, I’ve reported to our BOE and written about it here, that we have 32 of our 36 Native American seniors graduating. This just tells you that I have 32 seniors graduating. However, that doesn’t tell the cohort story. Six of those thirty-six students are of the 2002 cohort. This led me to ask, “what about the 2003 cohort?” How many students started in ninth grade in 2003 and should be graduating this year? Is it higher than the 48% of the 2002 cohort?

Short answer, Yes. In 2003, I had 48 students enter the ninth grade (the 2003 cohort). Of those 48 Native American students, six transferred to other schools and six will complete their graduation requirements this August or in 2008. Of the 42 Native American students I should have graduated this year, 27 will graduate Friday night. Eight have officially dropped out, one student has passed away. 64% of our 2003 Native American cohort is graduating, much better than the 48% who graduated in the 2002 cohort. The other piece of that puzzle is that five students from that 2002 cohort are graduating this year, having taken five years and raising the passing rate for their cohort. Unfortunately, any student who takes more than four years, who we keep and compel to return, still counts against a school district as a drop out.

I think sometimes that the different ways of looking at our results can be confusing to our community. Hopefully, this post helps to explain a piece of the reason why.

  1. Thank you for the clarification. Yes, explaining data gets complicated, that’s why we use data vs. words to simplify and summarize some things. Some of us use percentages (proportions based on units of 100) a little differently, perhaps also adding to some confusion.

  2. There are many essentially lying ways to look at these numbers. It is so gratifying to see that there are schools that analyze them in an honest way.

    We look at all our data in a critical way. As a result we get answers to the question “Where should we look more closely?” and that in turn points us to places where we can improve. But we have to start out with the idea that we’d like to do better. For many, this idea seems impossible.

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