Overview
Student Growth Percentiles and Accountability
References
The Colorado Growth Model:
A Technical Overview
Damian W. Betebenner
National Center for the Improvement of Educational Assessment
Dover, NH
CCSSO Conference on Student Assessment
Los Angeles, CA — June 23rd, 2009
Damian W. Betebenner The Colorado Growth Model
Overview The Colorado Growth Model
Student Growth Percentiles and Accountability Student Growth Percentiles: What Is
References Student Growth Percentiles: What Should Be
The Colorado Growth Model
Student Growth for Multiple Purposes
Growth as the cornerstone of accountability: In Colorado student
progress to judge state, district, school and student performance.
The Colorado Growth Model addresses three related questions
using the same metric:
What is the level of growth for a student (i.e. Actual Growth)?
What should the level of growth for a student be (i.e. Aspirational
Growth)?
What could the level of growth for a student be (i.e., Realistic Growth)?
Student growth percentiles—a normative description of
growth—forms the basis of the Colorado Growth
Model [Betebenner, 2008]
Damian W. Betebenner The Colorado Growth Model
Overview The Colorado Growth Model
Student Growth Percentiles and Accountability Student Growth Percentiles: What Is
References Student Growth Percentiles: What Should Be
Student Growth Percentiles
Normative Growth Question
Should we be surprised with a student’s current achievement given
their prior achievement?
Given a student’s prior scale scores and the associated conditional
density, their current scale score corresponds to a percentile of that
conditional distribution.
This percentile is the student’s growth percentile.
Growth percentiles are closely related to estimating the probability of
observing a student’s current achievement taking account of their
past achievement:
Pr(Current Achievement |Past Achievement ).
Growth percentiles describe the rarity of a student’s current
achievement conditional upon their prior achievement.
Damian W. Betebenner The Colorado Growth Model
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Overview The Colorado Growth Model
Student Growth Percentiles and Accountability Student Growth Percentiles: What Is
References Student Growth Percentiles: What Should Be
Student Growth Percentiles
Normative Growth Question
Should we be surprised with a student’s current achievement given
their prior achievement?
Student growth percentiles address this question.
Consider a low achieving student with 90th percentile growth and a
high achieving student with 10th percentile growth.
The low achieving student grew at a rate exceeding 90 percent of
similar students.
The high achieving student grew at a rate exceeding just 10 percent of
similar students.
The low achiever’s growth is more exemplary (probabilistically) than the
high achiever’s.
Judgments about the adequacy of student growth require external
criteria.
Damian W. Betebenner The Colorado Growth Model
Overview The Colorado Growth Model
Student Growth Percentiles and Accountability Student Growth Percentiles: What Is
References Student Growth Percentiles: What Should Be
Combining Actual and Aspirational Growth
What Is
Each student receives a growth percentile quantifying their growth in
each of three subject for the academic year.
What Should Be
Each student receives percentile growth projections/trajectories esti-
mating:
What level of growth is required to reach each of the 3
performance levels in 1, 2, 3, and 4 years.
What Could Be
The percentile metric establishes a normative foundation allowing
stakeholders to set challenging yet realistic goals.
Damian W. Betebenner The Colorado Growth Model
Not On Track to Reach Proficient − Not Catching Up
Colorado's Growth Model uses each student's growth percentile in two ways:
First, the growth percentile is used to describe how
73rd much a student has grown
95th●
during the last year. Second, the growth percentile is used to determine whether the
student is on track to reach/maintain proficiency. The following slides demonstrate,
for an individual student, how Colorado's Growth Model is used to determine
whether the student is On Track to Reach Proficient, that is "Catching Up".
7th ●
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
Is the student's growth,
from 2007 to 2008, sufficient
to put them on track to reach
proficient within 3 years?
73rd ●
95th ●
7th ●
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
Is the student's growth,
from 2007 to 2008, sufficient
to put them on track to reach
proficient within 3 years?
73rd ●
95th ●
After 1 year the student
7th ● remains partially proficient,
so their 1 year growth was not
enough to get them to proficient.
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
In 2007 CDE estimated that it would take
Is the student's growth, 92nd percentile growth, consecutively for two years, to reach proficient.
from 2007 to 2008, sufficient Their 73rd percentile growth puts them behind that 2 year target.
to put them on track to reach
proficient within 3 years?
92nd
73rd ●
95th ●
After 1 year the student
7th ● remains partially proficient,
so their 1 year growth was not
enough to get them to proficient.
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
In 2007 CDE estimated that it would take
Is the student's growth, 92nd percentile growth, consecutively for two years, to reach proficient.
from 2007 to 2008, sufficient Their 73rd percentile growth puts them behind that 2 year target.
to put them on track to reach
proficient within 3 years?
88th
92nd
73rd ●
95th ●
In 2007 CDE estimated that it
would take 88th percentile growth,
consecutively for three years, to reach
After 1 year the student proficient. Their 73rd percentile growth
7th ● remains partially proficient, puts them behind that 3 year target.
so their 1 year growth was not
enough to get them to proficient.
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
In 2007 CDE estimated that it would take
Is the student's growth, 92nd percentile growth, consecutively for two years, to reach proficient.
from 2007 to 2008, sufficient Their 73rd percentile growth puts them behind that 2 year target.
to put them on track to reach
proficient within 3 years?
Conclusion: Because the student was not proficient in 2008 and their 2007−08
growth percentile of 73 was less than both the two and three year targets, the
student's growth is considered to be insufficient to reach proficient within three years 88th
In short, the student is not on track to be proficient and is not "catching
92nd up".
73rd ●
95th ●
In 2007 CDE estimated that it
would take 88th percentile growth,
consecutively for three years, to reach
After 1 year the student proficient. Their 73rd percentile growth
7th ● remains partially proficient, puts them behind that 3 year target.
so their 1 year growth was not
enough to get them to proficient.
Grade 3/2005 Grade 4/2006 Grade 5/2007 Grade 6/2008 Grade 7/2009 Grade 8/2010
On Track to Remain Proficient − Keeping Up
Colorado's Growth Model uses each student's growth percentile in two ways:
First, the growth percentile is used to describe how
63rd ●
much a student has grown
during the ●last year. Second, the● growth percentile is used to determine whether the
66th
26th
student is on track to reach/maintain proficiency. The following slides demonstrate,
for an individual student, how Colorado's Growth Model is used to determine
whether the student is On Track to Remain Proficient, that is "Keeping Up".
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Is the student's growth,
from 2007 to 2008, sufficient
to remain at or above
proficient for the next 3 years?
63rd ●
66th ●
26th ●
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Is the student's growth, After 1 year the student
from 2007 to 2008, sufficient remains proficient,
to remain at or above so their 1 year growth was
proficient for the next 3 years? enough to remain at proficient.
63rd ●
66th ●
26th ●
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Is the student's growth, After 1 year the student
from 2007 to 2008, sufficient remains proficient,
to remain at or above so their 1 year growth was
proficient for the next 3 years? enough to remain at proficient.
63rd ●
66th ● 18th
26th ●
In 2007 CDE estimated that it
would take, at a minimum, 18th percentile growth,
consecutively for two years, to maintain
at or above proficient. Their 63rd percentile
growth puts them above that 2 year minimal target.
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Is the student's growth, After 1 year the student
from 2007 to 2008, sufficient remains proficient,
to remain at or above so their 1 year growth was
proficient for the next 3 years? enough to remain at proficient.
63rd ● 22nd
66th ● 18th
26th ●
In 2007 CDE estimated that it
would take, at a minimum, 22nd percentile
growth, consecutively for three years, to
In 2007 CDE estimated that it maintain at or above proficient. Their 63rd
would take, at a minimum, 18th percentile growth, percentile growth puts them above that 3 year
consecutively for two years, to maintain minimal target.
at or above proficient. Their 63rd percentile
growth puts them above that 2 year minimal target.
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Is the student's growth, After 1 year the student
from 2007 to 2008, sufficient remains proficient,
to remain at or above so their 1 year growth was
proficient for the next 3 years? enough to remain at proficient.
Conclusion: Because the student was proficient in 2008 and their 2007−08
growth percentile of 63 was greater than both the two and three year minimum targets, the
student's growth is considered to be sufficient to remain ●proficient during the next three years. 22nd
63rd
In short,
66th
the student is on track to remain proficient and is "keeping
18th
up".
26th ●
In 2007 CDE estimated that it
would take, at a minimum, 22nd percentile
growth, consecutively for three years, to
In 2007 CDE estimated that it maintain at or above proficient. Their 63rd
would take, at a minimum, 18th percentile growth, percentile growth puts them above that 3 year
consecutively for two years, to maintain minimal target.
at or above proficient. Their 63rd percentile
growth puts them above that 2 year minimal target.
Grade 5/2005 Grade 6/2006 Grade 7/2007 Grade 8/2008 Grade 9/2009 Grade 10/2010
Overview
Student Growth Percentiles and Accountability School Accountability
References
Going from Students to Schools
It’s of interest to examine schools where students demonstrate, on
average, extraordinarily high and low student growth.
To summarize the student growth percentiles associated with a
school (or other grouping) calculate the median of the student
growth percentiles.
If students were randomly assigned to schools, expect to see a
median of 50.
Values greatly above or below 50 are of interest in identifying best
practices or providing extra support.
Examining growth with achievement sheds new light on school
performance.
Damian W. Betebenner The Colorado Growth Model
District C: 2008 CSAP Math School Results
Student Growth versus Student Achievement by Percent Free/Reduced Lunch
School Percent
Higher Achievement Higher Achievement Free/Reduced Lunch
Lower Growth Higher Growth
Percent at/above Proficient in School
Less than 20 percent
● 20 to 40 percent
● 40 to 60 percent
● 60 to 80 percent
● More than 80 percent
School Size
50 Students
100 Students
200 Students
30 500 Students
1,000 Students
10 Lower Growth Higher Growth
Lower Achievement Lower Achievement
Median of Student Growth Percentiles in School
Overview
Student Growth Percentiles and Accountability
References
References
Betebenner, D. W. (2008).
Toward a normative understanding of student growth.
In Ryan, K. E. and Shepard, L. A., editors, The Future of Test-Based
Educational Accountability, pages 155–170. Taylor & Francis, New
York.
Damian W. Betebenner The Colorado Growth Model
About this copy
The Colorado Growth Model: A Technical Overview — CCSSO, June 2009.
This is an image-based copy of the original beamer slides; builds and animations are flattened.