ON THE PRECISION OF MCAS SGPS
Update on results presented to April 2013 TAC
BACKGROUND
• October 2012: Derived and reported precision results from simulations based
upon resampling at the state level.
• Fall 2012: State to transition to anchored SGP analyses (i.e., baseline referenced)
from previous cohort based analyses.
• April 2013: Derived and reported precision results based upon resampling at
the individual level for both cohort and anchored analyses.
• October 2013: Update of 2013 MCAS results based upon methodology
discussed April 2013
METHOD
• Precision estimates for individual SGPs are derived from resampling of SGPs
using CSEMs from MCAS assessment.
• Student scores (current and rst prior) are simulated using CSEM and SGPs are
re-calculated based upon perturbed scores.
• Source code for the simulation algorithm is available on GitHub at: https://
github.com/CenterForAssessment/SGP/blob/master/R/csemScoreSimulator.R
and CSEMs are available in the embedded SGPstateData meta-data object.
• 100 simulated SGPs are calculated for each student. Standard deviation of the
simulated SGPs is used as the standard error associated with the individual SGP.
• Simulated SGPs are calculated for both cohort and anchored SGPs. Anchored
SGPs utilize CSEMs averaged across multiple years.
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RESULTS
2013 MCAS Median SGP (anchored) Standard Errors by grade and
content area.
Grade 3 Grade 4 Grade 5 Grade 6 Grade 7 Grade 8 Grade 10
ELA --- 5.62 6.21 6.24 6.06 6.44 6.19
Mathematics --- 5.76 5.99 6.11 6.15 6.05 5.86
RESULTS
• The standard error associated with individual SGPs is
approximately 6 for each grande and content area.
• The maximum standard error associated with individual SGPs
is 8.85.
• In general, there is greater precision associated with extremely
low/high SGPs.
RESULTS: STANDARD ERROR BY PRIOR SCORE
SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP
ELA Grade 4 Std Error ELA Grade 5 Std Error ELA Grade 6 Std Error
Growth Theta (Prior) Growth Theta (Prior) Growth Theta (Prior)
SGP SGP SGP
SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP
ELA Grade 7 Std Error ELA Grade 8 Std Error ELA Grade 10 Std Error
Growth Theta (Prior) Growth Theta (Prior) Growth Theta (Prior)
SGP SGP SGP
RESULTS: STANDARD ERROR BY PRIOR SCORE
SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP
MATHEMATICS Grade 4 Std Error MATHEMATICS Grade 5 Std Error MATHEMATICS Grade 6 Std Error
Growth Theta (Prior) Growth Theta (Prior) Growth Theta (Prior)
SGP SGP SGP
SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP SGP Standard Error by SGP and Prior Growth Theta SGP
MATHEMATICS Grade 7 Std Error MATHEMATICS Grade 8 Std Error MATHEMATICS Grade 10 Std Error
Growth Theta (Prior) Growth Theta (Prior) Growth Theta (Prior)
SGP SGP SGP
About this copy
On the Precision of MCAS SGPs — Massachusetts Department of Education, October 2013.
This is an image-based copy of the original Keynote slides; builds and animations are flattened.