I promised you a nifty visualization of how the CPS Space Utilization formula (as it is currently calculated) affects neighborhood schools, and I’m finally delivering.  It look a little longer than expected because distilling slightly complicated math concepts into a straightforward visual is not very easy.

Luckily, I was given an infographics concept assist from the Aya O’Connor at the monthly Open Gov Hack Night/Data Potluck who helped me think through the potential messages that different graphic choices would send.  I then attempted to use her great ideas in my laptop copy of Omnigraffle.  (Aya, if the end result is less than crisp, it is definitely my fault NOT yours!  You rock!)

Through my conversations with CPS representatives about the A2A Space Utilization release, I was told by a Central Office employee that principals are to blame if class sizes are not kept to limits because they are given the choice for how to use their resources/budget from the District.

Really?  Hmm.  What does that look like exactly at the neighborhood school?

It puts principals in a no-win situation, actually.  When enrollments put homeroom sizes over the District’s maximum limits, principals could try and divide homerooms to keep class sizes down…at the expense of losing the rooms that they use for special education or bilingual instruction or music/art/tech.

It looks like this, according to CPS’ current space utilization formula, both terrible choices, but both considered to be efficient:


And whether the lower end of efficient or the higher end of underutilized?  Either school still looks pretty full, especially compared to the average K-8 homeroom class sizes in the State of Illinois ( ~22 students per homeroom**).


And just because she is brilliant, Aya made sure that each room depicted in each of the school graphics gets larger and smaller in proportion to the number of students in it.

For the complete comparison of the two formulas (CPS Current Formula and the Apples to Apples Adjusted Formula), you can click over here.

**Source: Illinois State Board of Education School Report Cards.

2 thoughts on “CPS Space Utilization Formula = Tough Choice for Principals

  1. Pingback: CPS Space Utilization Formula Comparison…the Summary | Apples 2 Apples in Chicago Public Schools

  2. Pingback: Space Utilization: Does Central Office Use 36 as the Average Maximum Class Size or Not? | Apples 2 Apples in Chicago Public Schools

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