Methods and limitations

Comparison groups:

Other non-selective schools: because charter schools are open-enrollment schools that cannot screen students, the most relevant student population for comparison is the group of students in other non-selective traditional district schools. Other non-selective schools within Chicago Public Schools must admit any student who lives in their attendance boundary.  While charter schools are non-selective, this category excludes charter schools.  Included in this category are magnet schools and contract schools.

Selective schools: because charter schools are always striving to reach a meaningful high standard, we have included averages among selective enrollment public schools as a more accurate representation of what charter schools are striving for.  Selective schools in our visualizations include schools classified by CPS as Selective, Classical, Career Academy, Military, or Regional Gifted Centers, Regional Gifted Centers, and those schools schools with selective admissions requirements according to the CPS High Schools Guide (Chicago High School for the Arts, Chicago High School for Agricultural Sciences, Michele Clark Academic Preparatory High School, Marie Sklodowska Curie Metropolitan High School, Frederick Von Steuben Metropolitan Science Center, Daniel Hale Williams Preparatory School of Medicine, Devry, Collins Academy High School, and Lincoln Park High School.)

Weighted averages: When metrics are reported at the school type level (e.g. the average charter school ACT mean score in 2012) these include averages across schools weighted by the total number of students in that school type in the “denominator” of the metric (e.g. the total # of ACT test takers in 2012).

Who’s included in the test scores: CPS makes most testing metrics available with and without English Language Learners.  We used reports that include English Language Learners.  Except for the ISAT % meets/exceeds data, CPS does not report performance of demographic subgroups at the school level.   If and when this data becomes available, we will include it in future visualization tools.

Who’s excluded from the portal:

Chicago schools: Alternative schools, Achievement Academies, Special Education schools, and the Alternative charter school Youth Connections Charter School were excluded from school type averages views and school performance views.

Schools outside Chicago: Illinois has a number of charter schools outside of Chicago providing quality educational options to their students.  We plan to include data for those schools in future iterations of the tool.  Limited data access prevented those schools from being included in the data portal at this time.

Data limitations:

The CPS reported high school graduation rate is the publicly available rate for all schools in the District - charter or otherwise.  This is a five year cohort rate (defined in our data definitions section) that reflects the number of 9th graders who start high school at a particular school who graduate from any other school in CPS. There is not a publicly available rate that tracks the number of 9th graders who begin at a given school who graduate from that school in a given timeframe.  Therefore, reporting school type level graduation rates, as you see in the Illinois Charter Overview landing page, has its limitations.  The graduation rates for Selective, Charter and Other Non-Selective public schools reflect the rate at which students who begin 9th grade in any given school type graduate from any other school in CPS, not necessarily from the same school or even the same school type.

The College Enrollment rate reported by the National Student Clearinghouse (defined in our data definitions section) reflects the number of students who graduated the prior school year who enroll in College by November of the school year in question.  Note that this rate cannot be combined with the CPS-reported 5 year cohort high school graduation rate.  While the high school graduation rate will refer to the number of 9th graders who began at the school in the “denominator” of the rate, the college enrollment rate refers to a different group of students - those who graduated the year prior, regardless of where or when they began 9th grade.