A Look at population trends in DC’s school population

I’m going my best to play it straight.

In the following fiew posts I will try to give you a clear look at how the publicly-funded student enrollment in Washington, DC has been trending over the past decade or so.

I’ll then make a few predictions of how I think things will continue in the next few years.

And then make some judgments on what these records mean.

I think that graphs are often one of the very easiest ways to make things clear, but as Darrell Huff wrote a long time ago in a classic work called “How to Lie With Statistics“, you can still use them in many ways to mislead if you want to.

Here is the very first graph given by DC’s Office of the State Superintendent of Education, or OSSE:

Looks like a huge jump, right? Maybe the latest enrollment is about twice as much as it was at its low point just after Rhee got here to save the day in 2008, right?

No.

It’s not such a huge jump.

And it’s for the regular DC public schools combined with the DC charter schools (privately run tho funded by taxpayers). Not just DCPS, which I’ll look at in a subsequent blog.

The scale is really misleading. The total population is in fact increasing, but (a) most of it seems to have occurred after Rhee left, and (b) from the current high of 80,854 from a nadir of 70,922 is only a 14% increase, or about one-seventh, not a doubling of population.

One’s eye wouldn’t trick one so if one used a scale that went all the way to zero on the vertical axis. (BTW, this is precisely one of Huff’s methods of lying with statistics!) So here is what I think is a fairer way to represent the data, with a scale that goes from 0 to 90,000.

You can see that over the past decade or so, there was a modest drop, followed by a modest rise. These are NOT huge changes, folks!

Is there something special and weird going on? Not really. The population of DC is rebounding somewhat, as well. Take a look at this graph prepared by Google and the US Census Bureau, not by me:

I hope it’s not a surprise that the school enrollment numbers and the total DC population of all ages do not move in lockstep! But, as a general rule, if you get more adults, they have a mysterious way of making babies, and those little’uns eventually do grow up and go to school somewhere!

About these ads
Published in: on October 25, 2012 at 11:49 am  Comments (2)  
Tags: , , , , , , ,

The URI to TrackBack this entry is: http://gfbrandenburg.wordpress.com/2012/10/25/a-look-at-population-trends-in-dcs-school-population/trackback/

RSS feed for comments on this post.

2 CommentsLeave a comment

  1. OSSE must have a copy of that book how to lie with statistics on every desk.

  2. Oh, Guy, you should be able to get census numbers on school age children separate from total population increase. It would be a better comparison.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 395 other followers

%d bloggers like this: