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There is a common perception that charter high schools do a better job than traditional public high schools in preventing kids from dropping out. Is that true? Guy Brandenburg, who writes the GFBrandenburg’s Blog (which is subtitled “Just a blog by a guy who’s a retired math teacher”), looked at some data in Washington D.C. and comes to an interesting conclusion.  Here’s the piece, from his blog:


By Guy Brandenburg

The conventional wisdom is that urban charter schools do a much better job than public schools at getting their students to graduate from high school and go to college.

But audited figures from the District of Columbia’s Office of the State Superintendent of Education over the past ten years show that despite all the advantages and extra corporate funding of charter schools, the attrition rates from both types of schools is essentially the same, and is very high.

The graphs and tables below show that both public and charter schools in Washington D.C. have a serious attrition problem, in that large proportions of the students enrolled and counted in October of their 9th grade have somehow vanished by the time that the cohort of 12th graders is officially counted in October.

This attrition rate is serious in both cases: over the past decade, about 44 percent of the high school freshmen (9th graders), in BOTH the D.C. public schools and the D.C. charter schools, have gone missing when it is time for them to be counted as seniors (12th graders). The differences in attrition rates are trivial: 43 percent for the charter schools and 45 percent for the public schools.

Our data does NOT tell us where these students have gone. Some probably moved or transferred to another state, or went to a private or parochial school, or have been incarcerated, but a significant fraction of them of them probably flat-out dropped out of school. It would be wonderful if there was a source of data that tracked where these students actually went, but let’s not hold our breath waiting for that data to be gathered and released.

Think of the advantages of the charter schools in recruiting their students: a parent has to somehow navigate the application system, fill out the lottery form, appear for interviews, and agree to the behavior and attendance and work requirements — all of which will eliminate a large fraction of the hardest-to-reach students who have parents who are simply non-functional. However, for all of their boasts of 100 percent graduation rates, the D.C. charter schools either expel or push out large fractions of their incoming high school students, or those students withdraw on their own (for whatever reasons we can only guess at).

guy 1



guy 2


Other than the colors and the total count of students, you will not notice much of a difference between the two graphs shown above. The first one shows how the students in the regular DC public high schools have been disappearing from the rolls (or not) over the past 9 years, and the second one shows how the students in the DC charter high schools have been disappearing over the past 8 years.

My conclusion?

High school dropouts are a very serious problem in Washington D.C., and that attrition rate is virtually the same in both the regular public schools and in the charter schools. The charter schools do NOT have a magic wand that has solved the problem.


I also attach charts showing the entire enrollment, by grade level and year, for all of DC public schools and all of the DC charter schools, for the past decade. These tables were painstakingly gathered by Erich Martel, a retired DC social studies teacher (last at Phelps and Wilson), who has been raking through files showing administrative malfeasance for a very long time in the administration of DC public schools. His source has been the official audited enrollment figures published by OSSE (Office of the State Superintendent of Education).

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guy charter

The colors are important here, because they allow you to follow a cohort, or age-group, diagonally down and to the right, as they proceed through their years in school. For example, the charter school “Class of 2012″ in our last graph is the magenta diagonal that reaches the 12th grade in 2011-12. This group started in the fourth grade, in SY 2003-4, with 843 students. The next year, in 5th grade, in SY 2004-5, it had 919 students. Obviously some students entered this cohort at some point between October 2003 and 2004 (and most likely some kids departed as well; the data does not tell us how much churn took place, only the net loss or gain). This magenta-colored cohort reached its maximum size in the 7th grade, with two thousand, one hundred nineteen students. By the beginning of 9th grade, that cohort had 1,971 students, and by October of 2011, at the beginning of their senior year, the overall charter school cohort that I am calling the “Class of 2012″ had shrunk to 987 students,  which is almost exactly half the size that it was when it began the 9th grade in 2008 with 1971 students. So I say that the attrition rate for that class was 50 percent, since 50 percent of the incoming high school freshman class has somehow vanished by the time that the rest of the cohort reached 12th grade.

I am not aware of any single D.C. charter school or traditional public school that goes all the way from pre-school through 12th grade. However, as far as I have seen, every public or charter school that offers 9th grade now goes all the way to 12th grade, so it seems quite fair to examine the attrition rate for charter and regular public schools as a whole.

In the regular public schools, that same class went from 5,375 students in October 2002, when they began third grade, to 2,972 students when they began 8th grade in 2007, to 4,571 students when they began the 9th grade in 2008, and shrunk to 2,114 students when they began the 12th grade in 2011, for a high-school attrition rate of 54 percent for that particular age-group.

I notice something very weird about the regular D.C. public school enrollment figures: there is an enormous jump in enrollment from 8th grade to 9th grade, and then a large drop from 9th grade to 10th grade. My colleagues who teach high school tell me that this is because large numbers of students are made to repeat 9th grade; some of them are eventually skipped past the 10th grade, in part because administrators don’t want them to have to take the 10th grade DC-CAS standardized test, because their scores would be low.

Notice that over the past decade, the 9th grade D.C. public school enrollment has totaled over 50,000 students, larger than any other grade, which is awfully fishy, since the 8th grade total enrollment over that time was only about 36,000 students and 10th grade total enrollment was a bit under 38,000 students.

Since the 9th grade DCPS enrollment figures seem artificially inflated (by a LOT), one might conclude that the attrition rates calculated in this post for D.C. public schools are higher than they ought to be.


But however you measure it, attrition is a very serious problem in DC, and nobody has solved it.


If you want to see the attrition rates at individual D.C. charter schools, look here.


(Update: A few of the charters fell out of the post in an earlier version. They are restored here.)