Georgia Skip Year SGP Analyses
A Historical Comparison of the 2019 SGP Results
Damian Betebenner & Adam Van Iwaarden
National Center for the Improvement of Educational Assessment (NCIEA)
Georgia EE TAC — Atlanta, GA (and Virtual, USA)
Friday, November 20th, 2020
This work is licensed under a
Creative Commons Attribution 4.0
International License.
The Scene
• We all know the situation
▪ Global pandemic
▪ Cancellation of in-person education in the Georgia in
spring 2020
▪ Suspension of state summative testing and accountability
for 2019-2020 school year
▪ K-12 education for the 2020-2021 school year in mixed
remote and in-person format.
▪ Lack of clarity on state summative testing and
accountability for 2020-2021 including the use and
calculation of academic student growth
Spoiler Alert
• Should Georgia calculate student growth? Yes!
▪ SGP calculation is more important now than ever.
▪ Student growth can be used in many ways (not usually
done for accountability) to help schools and districts
assess and ameliorate the impact of COVID-19.
▪ School interruption in spring 2020 and non-normal and
disparate education in this academic year could impact
"opportunity to learn" for some groups more than
others.
▪ Indicators of student mode of education (e.g., remote,
in-person, hybrid) could help Georgia to quickly ascertain
what worked best to educate students under pandemic
related circumstances.
Spoiler Alert
• Should Georgia use student growth for education accountability
in 2021? Problematic!
▪ Need to substitute skip-year growth (two-year growth
from 2019 to 2021) for usual one-year growth.
▪ Historical skip-year analyses provide a useful frame of reference
for 2021 growth results, but do not unequivocally support or
reject their use in accountability calculations.
▪ Given disruptions to student education, we anticipate 2021
skip-year analyses will deviate substantially from the historical
skip-year analyses.
▪ The issue is only partly technical in nature. There are large
pragmatic and political components to consider.
▪ Overall and differential impacts of COVID-19 on student
education should inform accountability policy decisions.
Presentation Overview
• How skip-year analyses were organized and conducted
• Results for End-of-Grade (EOG) and End-of-Course subjects
▪ student level
▪ school level
• Generalized trends in results for demographic subgroups
Skip-year SGP Calculation
• Calculating skip-year (2017 to 2019) growth is no more
difficult technically than calculating one-year growth.
▪ Georgia calculates skip-year growth regularly as part of
EOC SGP analyses.
▪ Calculating skip-year growth involves changing the
configurations that define what years, content areas,
grades are used to calculates SGPs.
Skip-year SGP Calculation
• Data from Georgia Milestones, excluding 2018.
• Same SGP "configurations" (i.e. unique grade by content area by
year) used in the traditional 2019 were used, again, excluding
2018. We added an additional prior year to maintain the same
number of priors used in the calculations.
• All 4th grade analyses are eliminated because they rely on a single
prior test score and no prior test score exists (i.e., 2nd grade).
▪ This effectively removes 1/3 to 1/2 of kids included in
elementary school growth aggregations.
• Some EOC configurations were also eliminated due to a single
prior test restriction (e.g., course repeaters), but they may have
been included in other course progressions.
• Same restrictions were used for cohort size (1,500), etc.
Skip-year SGP Calculation
• Overall, SGP calculation rates were still very high.
• When both one- and skip-year SGPs could be calculated for a
given student:
▪ 87.9% of students with a one-year SGP also had a skip-
year SGP.
▪ 5% of students with a one-year SGP did not have skip-
year growth calculated
▪ 1.3% of students had a SGP calculation for the skip-year
analysis but not one-year
▪ 5.8% of students had neither a one- or skip-year SGP
Individual Student Results
• It is not defensible to assert that one-year SGPs are synonymous
with skip-year (two-year) SGPs. They represent growth over
different time spans.
• However, one- and skip-year SGPs are highly correlated – range
0.76 to 0.85 for all grade/content areas
▪ This is slightly lower than other states for whom we have done
historical skip-year analyses. This is primarily attributable to
the use of ranked SIMEX SGPs instead of non-measurement
corrected SGPs.
• Very similar (uniform) distribution – mean ~50 and SD of ~29
• Scale score correlations between current (2019) and most recent
prior did not decrease dramatically (2017 to 2019 correlation
was ~0.03 lower, on average).
Individual Student Results
• While high correlations show a strong linear relationship,
there were still many students with large differences.
▪ 20% of students had SGP differences of 21 or more.
• This is not surprising as many student's observed scores
can vary greatly from one year to the next, leading to highly
discrepant SGPs.
• Students that did not have a skip-year SGP calculated were
found to be slightly lower achieving (Z-score = ~-0.2) and had
typical one-year growth (SGP = ~51).
School Level Results
• Given that all 4th grade SGPs are missing from the skip-year
analyses, school level results were summarized in two ways:
▪ Including all students in a school for one-year summary
statistics (to show the total impact on school growth)
▪ Including the subset of students from grades in which
skip-year SGPs could be calculated (to give a more direct
comparison of the SGP differences).
• All school level summaries are calculated using schools with
at least 15 students.
School Level Results
• Slight changes in the correlations between school growth
and prior achievement were noted in all content areas.
• Mean SGP (MSGP) distributions were similar, with SD
increasing slightly.
• Correlations between one-year and skip-year MSGPs were
high for all content areas (range 0.83 to 0.98)
School Level Results
School Level Results
• Absolute differences between MSGPs were neither
insignificant nor egregious.
School Level Results
School Level
Results
• One factor that
appears to have a
significant impact
on school MSGP
differences is school
size. Nearly all
MSGP differences
greater than 5
percentile points
were from schools
with N < 250.
Demographic Group Results
• SGP calculation rate decline in skip-year analyses are usually
not much different for select demographic groups.
▪ One exception is English Learners.
• No notable differences in SGP distributions or correlations.
• Growth gaps observed in one-year analyses are compounded
in skip-year analyses (two years of growth gap in a single
measure). But not doubled!
Demographic Group Results
• At the school level, we typically see a negative relationship
between MSGP and percent demographic group.
Demographic Group Results
• We also see relatively small negative relationships between
MSGP differences and percent demographic group.
Accountability versus accountability
• Results of these analyses do not unequivocally disqualify the use
of skip-year growth in lieu of one-year growth.
• They do not unequivocally qualify their use either.
• This finding misses a larger point: It is questionable whether the
theory of action behind traditional accountability is appropriate
this year.
• Responsibility for student learning during a pandemic are different
and much more complex than during pre-pandemic education.
• Learning loss associated with COVID-19 is non-uniform across all
students, content areas, grades, and demographic subgroups.
• It is critical to understand who to treat and how much they need to
be treated (little “a” accountability)
• Growth data can be used for that purpose.
Accountability versus accountability
• Both overall COVID 19 learning loss as well as differential impact on
subgroups can be investigated with skip-year SGP data.
• Using baseline SGPs (discussed separately) overall impact can be
investigated at various levels (e.g., content area, grade, demographic
subgroup).
• Issues around opportunity to learn can be investigated using growth
gap comparisons for relevant demographic subgroups.
• For example, calculating mean SGP for students receiving education
remotely versus in-person.
• Investigations of (differential) impact on student achievement and
growth for already at-risk student populations will be critical to help
ameliorate impacts of the disruption to education from the COVID-19
pandemic.
• It is critical for the state to collected COVID 19 related variables (e.g.,
remote, hybrid, in-person schooling).
Summary
• Results of these analyses do not unequivocally disqualify the
use of skip-year growth in lieu of one-year growth.
• They do not unequivocally qualify their use either.
• Need confirmation that 2021 skip-year deviations are no larger
than they were historically.
▪ We are not optimistic this criteria will be met!
• Recommend that growth be calculated regardless of whether it
is used for accountability.
• Critical to the investigation of COVID-19 related learning loss
will be accurate data on COVID-19 related education programs
and student participation over time.
Question for TAC
1. If Georgia must use SGPs for Accountability in 2021, what should we consider
for calculating progress?
About this copy
Georgia Skip Year SGP Analyses — Georgia Department of Education, November 20, 2020.
This is an image-based copy of the original PowerPoint slides; builds and animations are flattened.