Overview
Growth Model Background
Student Growth Percentiles, Accountability and Program Evaluation
References
Student Growth with the MCAS
An Overview of Student Growth Percentiles
Damian W. Betebenner
National Center for the Improvement of Educational Assessment
Dover, NH
Malden, Massachusetts June 9th, 2009
Damian W. Betebenner Student Growth with the MCAS
Overview
Growth Model Background
About Me
Student Growth Percentiles, Accountability and Program Evaluation
References
Relevant Topics
What questions does the Massachusetts Growth Model address?
What are student growth percentiles and percentile growth
projections/trajectories?,
What role do the results from the Massachusetts Growth Model play
in program evaluations like those associated with ELT.
Damian W. Betebenner Student Growth with the MCAS
Overview
Growth Model Background
About Me
Student Growth Percentiles, Accountability and Program Evaluation
References
About Me
Damian Betebenner Senior Associate Center at Center for Assessment.
Developed student growth percentiles and percentile
growth trajectories[Betebenner, 2008] to help states
discuss student growth. Currently refining and sharing
these techniques with other states including
Massachusetts, Colorado, Nevada, Indiana, South
Carolina, Arizona, Rhode Island.
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
What are the relevant questions for parents?
Yen (2007), from a state survey of parents, teachers and administrators,
compiled a list of frequently voiced questions/concerns by stakeholder
group.
Parent Questions
Did my child make a year’s worth of progress in a year?
Is my child growing appropriately toward meeting state
standards?
Is my child growing as much in Math as Reading?
Did my child grow as much this year as last year?
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
What are the relevant questions for teachers?
Yen (2007), from a state survey of parents, teachers and administrators,
compiled a list of frequently voiced questions/concerns by stakeholder
group.
Teacher Questions
Did my students make a year’s worth of progress in a year?
Did my students grow appropriately toward meeting state
standards?
How close are my students to becoming Proficient?
Are there students with unusually low growth who need special
attention?
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
What are the relevant questions for administrators?
Yen (2007), from a state survey of parents, teachers and administrators,
compiled a list of frequently voiced questions/concerns by stakeholder
group.
Administrator Questions
Did the students in our district/school make a year’s worth of
progress in all content areas?
Are our students growing appropriately toward meeting state
standards?
Does this school/program show as much growth as that one?
Can I measure student growth even for students who do not
change proficiency categories?
Can I pool together results from different grades to draw
summary conclusions?
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Descriptive Questions
Note that the questions put forward by stakeholders are primarily
descriptive
The questions are only peripherally associated with causality.
High stakes accountability has transformed questions about student
growth into questions about responsibility/cause: Teacher and
School Effectiveness.
Again, starting with descriptive questions, perhaps the place to
begin is with description and a model supporting such ends.
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Descriptive Accountability
Accountability system results can have value without making
causal inferences about school quality, solely from the results of
student achievement measures and demographic
characteristics. Treating the results as descriptive information
and for identification of schools that require more intensive
investigation of organizational and instructional process
characteristics are potentially of considerable value. Rather
than using the results of the accountability system as the sole
determiner of sanctions for schools, they could be used to flag
schools that need more intensive investigation to reach sound
conclusions about needed improvements or judgments about
quality [Linn, 2008, p. 21].
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Describing Student Growth
Measuring student growth, even with a vertical scale, is not a simple
task.
Some believe a vertical scale simplifies the task of measuring
student growth.
Even with an interval (or ratio) scale, growth is not easy to interpret.
Consider, for example, height.
A child might grow 4 inches between ages 3 and 4.
4 inches is a well understood quantity.
The 4 inch increase becomes really meaningful only when understood
alongside the growth of other 3 to 4 year olds.
Student growth percentiles were developed to provide a normative
context for describing student growth.
Damian W. Betebenner Student Growth with the MCAS
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Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Student Growth Percentiles
Should we be surprised with a child’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 ).
As such, growth percentiles describe the rarity of a student’s current
achievement conditional upon their prior achievement.
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Student Growth Percentiles
Should we be surprised with a child’s current achievement given their
prior achievement?
Student growth percentiles answer 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 Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Model for Student Growth Percentiles
Student growth percentiles are calculated using quantile regression
with B-spline smoothing, a generalized additive model.
Quantile regression is used to model the complete distribution of the
response variable (current achievement)
B-spline smoothing is uses to accommodate non-linearity and
heteroscedasticity of the data.
The model/method is descriptive and all about data fit—it’s a data
mining procedure.
The model quantifies distance = rate · time probabilistically.
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Model for Student Growth Percentiles
Conditional Decile Regression Curves Conditional Decile Regression Lines
2006−07 Math: Grade 5 versus 6 2006−07 Math: Grade 5 versus 6
1000 Unsatisfactory Partially Prof. 1000 Unsatisfactory Partially Prof.
Proficient Proficient
Partially Prof. Proficient Advanced Partially Prof. Proficient Advanced
Grade 6 Scale Score Grade 6 Scale Score
Grade 5 Scale Score Grade 5 Scale Score
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Description, Inference, and Causality
Richard Berk in Regression Analysis, A Constructive Critique (2003)
provides an account of the (ab)use of regression
Three Cheers for Description Descriptive models are judged by their
utility
Two Cheers for Inference Inferential models are judged based upon their
ability to fulfill statistical criteria associated with
generalizing from a sample to a population. What is the
chance process?
One Cheer for Causality Causal models are judged, in addition to
inferential issues, by an external theory which plausibly
relates causes/interventions and effects/outcomes.
Damian W. Betebenner Student Growth with the MCAS
Relevant Questions/Concepts
Overview Description, Inference, and Causality
Growth Model Background Describing Student Growth
Student Growth Percentiles, Accountability and Program Evaluation Student Growth Percentiles
References Model & Software for Student Growth Percentiles
Criterion Referenced Growth
Combining Normative and Criterion-Referenced Growth
Growth adequacy is determined by whether a student’s growth is
sufficient to reach/maintain desired achievement levels (e.g.,
proficiency).
Percentile growth projections/trajectories are calculated for each
student using the most recent historical MCAS longitudinal student
growth analyses.
These “growth-to-standard” trajectories indicate what it will take for
the student to reach/maintain proficiency and other achievement
levels.
This approach to quantifying “adequate” growth (done by Colorado)
was approved by the USED for use in AYP determinations as part of
the Growth Model Pilot Program.
Damian W. Betebenner Student Growth with the MCAS
Advanced Reading
High Achievement
CSAP Reading
● Typical ● Scale Score
Proficient Low Growth
● ● Level Percentiles
● High 66th − 99th
Part Proficient Typical 36th − 65th
Low 1st − 35th
Unsatisfactory
Grade 5 Grade 6 Grade 7 Grade 8 Next Year
Scale Score 589 617 617 657
Achievement Level Proficient Proficient Part Proficient Proficient Achievement
Growth Percentile 64 36 83
Growth Level Typical Typical High Growth
Overview
Growth Model Background School Accountability
Student Growth Percentiles, Accountability and Program Evaluation Growth & Effectiveness
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 Student Growth with the MCAS
Boston: 2008 MCAS ELA School Results
Student Growth versus Current Student Achievement by Free/Reduced Lunch Percentage
School Percent
Free/Reduced Lunch
2008 Percentage at/above Proficient (Current Achievement)
Lower Growth Higher Growth ● Less than 20 percent
● 20 to 40 percent
Higher Achievement Higher Achievement ● 40 to 60 percent
70 ● 60 to 80 percent
● More than 80 percent
School Size
50 Students
100 Students
200 Students
Lower Growth Higher Growth 500 Students
Lower Achievement Lower Achievement 1,000 Students
2008 Median of Student Growth Percentiles in School
Boston: 2008 MCAS Math School Results
Student Growth versus Current Student Achievement by Free/Reduced Lunch Percentage
School Percent
Free/Reduced Lunch
2008 Percentage at/above Proficient (Current Achievement)
Lower Growth Higher Growth ● Less than 20 percent
● 20 to 40 percent
Higher Achievement Higher Achievement ● 40 to 60 percent
70 ● 60 to 80 percent
● More than 80 percent
School Size
50 Students
100 Students
200 Students
Lower Growth Higher Growth 500 Students
Lower Achievement Lower Achievement 1,000 Students
2008 Median of Student Growth Percentiles in School
Overview
Growth Model Background School Accountability
Student Growth Percentiles, Accountability and Program Evaluation Growth & Effectiveness
References
Growth, Effectiveness, and Value-Added
Fundamental Premise
“Good” schools bring about student growth in excess of that found at
“bad” schools.
“Good schools” are often called highly effective schools.
What’s the relationship between growth and effectiveness?
Effectiveness indicates who/what is responsible for the growth
(value-added models).
Damian W. Betebenner Student Growth with the MCAS
Economic Disadvantage vs School Effectiveness
TN Elementary Schools 2008
Average Yearly Achievement Gain 1
Math & Reading/Language Arts in Z units from
TN Current State Average
Percent Free & Reduced Lunch
2008 CSAP Reading:
School Median Student Growth Percentile versus School Percent Free/Reduced Lunch
School Size
50 Students
100 Students
Median of Student Growth Percentiles in School
200 Students
70 500 Students
1,000 Students
Percent Free/Reduced Eligible Students in School
2008 CSAP Math:
School Median Student Growth Percentile versus School Percent Free/Reduced Lunch
School Size
50 Students
100 Students
Median of Student Growth Percentiles in School
200 Students
70 500 Students
1,000 Students
Percent Free/Reduced Eligible Students in School
Figure 4c: Grade 6 (2006) Layered Model versus Quantile Regression Estimates (SEP3ML Scale)
by Prior Achievement Quintile (School Size >= 50)
Prior Achievement
1st Quintile
2nd Quintile
● ● 3rd Quintile
4th Quintile
Median Student Growth Percentile
70 ●●●● 5th Quintile
●●●● School Size
25 Students
● 50 Students
100 Students
●● ● 250 Students
● ● 500 Students
Value−Added Estimate from Layered Model
Overview
Growth Model Background
Student Growth Percentiles, Accountability and Program Evaluation
References
References
Berk, R. A. (2003).
Regression Analysis: A Constructive Critique.
Sage, Thousand Oaks, CA.
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.
Linn, R. L. (2008).
Educational accountability systems.
In The Future of Test-Based Educational Accountability, pages 3–24.
Taylor & Francis, New York.
Yen, W. M. (2007).
Vertical scaling and No Child Left Behind.
In Dorans, N. J., Pommerich, M., and Holland, P. W., editors, Linking
and Aligning Scores and Scales, pages 273–283. Springer, New
York.
Damian W. Betebenner Student Growth with the MCAS
About this copy
Student Growth with the MCAS An Overview of Student Growth Percentiles — Massachusetts Department of Education, June 9, 2009.
This is an image-based copy of the original beamer slides; builds and animations are flattened.