Illinois 2020 Skip-Year SGP Analyses
Damian Betebenner
National Center for the Improvement of
Educational Assessment
Illinois State Board of Education (ISBE)
Assessment and Accountability Technical Advisory Committee (TAC)
June 4, 2020
COVID-19 Pandemic
• Oh what a difference a couple of months make.
• Most Spring 2020 tests have been cancelled:
– State assessments in ELA/Math have been cancelled
– Many ELP assessments (WIDA/ACCESS) were completed, at least by most students in the state
• States, including Illinois, have been given assessment and accountability
waivers by ED for 2020.
• Because student academic growth as measured by state summative
assessments utilizes prior assessment data in its calculation, the impacts of the
2020 pandemic will have ripple effects in 2021.
• My colleague Adam VanIwaarden and I wrote a blog post on this topic in April
which can be found here: https://www.nciea.org/blog/sgp/issues-and-
considerations-covid-19-pandemic-presents-measuring-student-growth
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2021 SGP Calculation
• I have discussed whether growth can be calculated in 2021 and whether it can
be used for accountability (e.g., school or teacher) with more than two-dozen
states.
• Simple answer: Yes, SGPs can be calculated using 2019 (and earlier data) as
priors.
– Several states have been calculating two-year growth for years when there is not annual
sequence of tests. For example, 8th to 10th grade growth in ELA or Mathematics or End of
Course testing.
– Growth projections which yield Adequate Growth Percentiles (AGPs) will also be calculable in
• The harder question is whether these SGPs can/should be used as part of state
accountability.
– Are two-year SGPs valid as indicators of annual growth?
– Beyond technical viability, is it tenable (e.g., politically) to use two-year SGPs as a substitute for
one-year SGPs?
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2021 SGP Calculation
• Are two-year SGPs valid as indicators of annual
growth?
– The paper on which this presentation is based shares some
findings and will be discussed hereafter.
• Is it tenable (e.g., politically) to use two-year SGPs as
a substitute for one-year SGPs?
– A much harder question that likely differs from state to state.
– Answering it well requires technical due diligence which,
hopefully, this report/presentation begins to address.
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Illinois SGP Calculation
• Illinois, as a member of the PARCC consortium has
had SGPs calculated since Spring of 2016.
• Illinois assesses students in ELA and Mathematics in
grade 3, 4, 5, 6, 7 and 8.
• As mentioned previously, there is no summative data
in 2020 due to the COVID-19.
• To investigate the use of two-year SGPs in lieu of one-
year SGPs, we used historical data as follows
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Illinois SGP Calculation
• Using historical data from 2016 to 2019, two-year
SGPs from 2017 to 2019 were calculated using 2019
as the dependent variable and 2016 and 2017 as the
independent variables (i.e., order 1 and 2 SGPs)
– Two-year SGPs are calculated for grades 5, 6, 7, 8 in ELA and
Mathematics.
– SGPs are calculated separately for each norm-group.
• One-year SGPs from 2018-2019 were available from
previous SGP analyses.
– One-year SGPs are calculated for grades 4, 5, 6, 7, and 8.
– SGPs are calculated separately for each norm-group.
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Illinois SGP Results
• Frequencies associated with SGPs.
• In general, there are between 135,000 and 140,000
students with SGPs in each grade and content area.
• Note when more priors are used, the count decreases
slightly due to some students not having the
additional prior.
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Illinois SGP Results: Individual
• Correlations between two-year SGPs and one-year
SGPs (of order 2) were all high.
– Correlations ranged from 0.85 to 0.9 across grades and content
areas.
– When one-year/order 1 SGPs are considered, correlations drop
to 0.65 to 0.7. This is likely due to the fact that the 2017 score is
not a part of both one- and two-year analyses.
• Differences between individual SGPs can be large.
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Illinois SGP Results: School Level
• School level data was not provided as part of Pearson data
sets. We substituted another states data for this part until IL
school data becomes available.
• Correlations between two-year mean SGPs and one-year mean
SGPs (of order 2) were all high, higher than at the individual
level.
– Correlations ranged from 0.9 to 0.95 across grades and
content areas.
• Differences between two- and one-year mean SGPs can be
large.
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Illinois SGP Results: School Level
• For context, the year-to-year correlations between mean
school SGPs is approximately 0.5 to 0.6.
• Model-to-model (i.e., one-year to two-year) SGP correlations
are much higher than year-to-year correlations implying that
changing student populations
• Correlations of 0.9 are common in comparisons between SGP
and VAM.
• SGP differences of 5 correspond to an effect size of 0.18.
– The majority of mean SGP difference correspond to small effect sizes.
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For more information:
Center for Assessment
www.nciea.org
About this copy
Illinois 2020 Skip-Year SGP Analyses — Illinois Technical Advisory Committee, June 3, 2020.
This is an image-based copy of the original PowerPoint slides; builds and animations are flattened.