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Form Effects on the Estimation of Students’ Progress in Oral Reading Fluency using CBM. David J. Francis, University of Houston Kristi L. Santi, UT - Houston Chris Barr, University of Houston CRESST September 8, 2005. Overview. - PowerPoint PPT Presentation
Citation preview
Form Effects on the Estimation of Students’
Progress in Oral Reading Fluency using CBM
David J. Francis, University of Houston Kristi L. Santi, UT - Houston
Chris Barr, University of Houston
CRESST September 8, 2005
Overview
Curriculum Based Measurement (CBM) to Monitor Student Progress and Inform Instruction
Methods Results Conclusions
Background
Report of the National Reading Panel (NRP, 2000) highlighted the importance of instruction and assessment in five domains of reading and related skills
Phonemic awarenessPhonicsFluencyVocabularyComprehension
Background
No Child Left Behind (NCLB) and Reading First (RF) are based on the NRP model of reading acquisition and mastery
RF emphasizes The five domains, Three-tier model of instruction, prevention and
intervention, Four purposes of assessment in guiding
instruction
Purposes of Assessment
Reading First describes four purposes for assessment in the five domains: Screening Diagnosis
Progress Monitoring Outcome
All in the service of guiding instruction
Progress Monitoring
Monitor student progress toward year-end goals
Provide teachers regular feedback on students’ rate of skill acquisition
Identify students needing modification to current instruction based on low rate of skill acquisition
Progress Monitoring
Essential characteristics Administer on a regular basis Brief and easy to administer in the classroom Provide scores on a constant metric Predictive of end of year outcomes Free from measurement artifacts such as practice
effects and form effects
CBM has been proposed as having these properties
What is CBM?
Students read connected text for a fixed duration of time, typically one minute
Oral reading fluency (WCPM) is computed and charted as a measure of growth in reading rate
Reading materials range from basal readers to pre-packaged texts
DIBELS Developed by Good and Kaminski CBM measure of early reading skills using
one minute probes Included in this study due to
A large number of stories are in place for fluency assessment
Developers’ efforts to equate stories for “readability” Ubiquitous in RF for PM assessment
Many Strengths
Quick, easy assessment One minute probe given once a week Teacher friendly format Easy to follow directions Instructionally relevant information Within grade evaluation of student growth
Why might we expect form effects?
Story construction Readability formulas are not perfect Difficult to precisely control text features that
affect fluency Lack of attention to scaling
Stories have been pre-equated for text features
No attempt to empirically equate forms Assumption that WCPM provides a constant
scale
Purpose of Current Study
Examine form effects on DIBELS Oral Reading Fluency (DORF) at single time point in grade 2
Examine form effects on inferences about growth in DORF over 6 weeks in grade 2
Methods
Setting and Participants
Two schools in HISD 134 students
85 from school A 49 from school B 69 females 65 males
Ethnically diverse student populations
Measures
DORF Passages (n=29) Six passages were randomly selected
Spache readability index average = 2.65 Range 2.6 to 2.7
Degrees of Reading Power readability index = 45.67 Range 44 to 46 Scale 0 (easy) to 100 (difficult)
Procedures
3 research assistants administered the probes to all students once every two weeks
Inter-rater reliability of .85 established prior to start of study
Passages administered according to guidelines provided in DIBELS manual
Story order randomly assigned (1 of 6) Three stories read at baseline One story read in waves 2-4
Random Assignment of Students to Passages Each student read three passages at baseline Design allows estimation story, order, and story by order effects
GROUP BABY BOOK COLOR HOME POOL TWIN
A 1 2 3
B 1 2 3
C 1 2 3
D 1 2 3
E 3 1 2
F 2 3 1
Despite randomization of students to six groups, group differences in fluency were apparent at baseline Using a measure of fluency from the Texas
Primary Reading Inventory (TPRI), the six groups differed in mean fluency
F(5,118) = 3.98, p < .002 Means ranged from 47 to 80 WCPM across the 6
groups
Subsequent analyses used TPRI fluency as a covariate
When TPRI fluency is covaried, groups do not differ on any particular form/story.
Note we’re not saying that DIBELS stories are equal, only that for any given story, groups did not differ in performance after controlling for TPRI fluency.
Data Analysis
Analyzed oral reading fluency using mixed model approach to repeated measures analysis of variance using SAS PROC MIXED
Fixed effects Random effects: TPRI_Fluency(TPRI_story) Story Correlations DIBELS_Story (1-6) (By Order) DIBELS Order (1,2,3) DIBELS_Story by Order
Results
Descriptive Data
ORDER BABY BOOK COLOR HOME POOL TWIN
1 M 76.00
SD 34.04
M 66.30
SD 35.58
M 82.58
SD 28.39
M 105.37
SD 35.22
M 93.26
SD 34.03
M 69.83
SD 22.54
2 M 78.21
SD 29.66
M 71.10
SD 32.43
M 78.68
SD 31.28
M 95.44
SD 38.23
M 81.85
SD 36.05
M 105.55
SD 30.35
3 M 69.00
SD 29.03
M 66.46
SD 27.04
M 111.00
SD 35.83
M 81.50
SD 35.18
M 82.38
SD 35.79
M 95.21
SD 35.47
Grand Mean
M 74.33
SD 30.65
M 67.91
SD 31.18
M 89.41
SD 34.24
M 93.86
SD 36.91
M 85.65
SD 35.12
M 88.83
SD 32.84
Grand
Mean
M 81.53
SD 33.65
M 84.40
SD 34.20
M 83.13
SD 35.74
M 83.02
SD 34.47
Tests of Fixed Effects
EFFECTNUM
DFDEN DF
F VALUE
Pr > F
TPRI_FLUENCY(T_STORY) 5 226 117.8 <.0001ORDER 2 226 2.4 0.0931DIBELS STORY 5 226 19.0 <.0001DIBELS STORY X ORDER 10 226 0.75 0.6798
Pairwise Differences in LS Means
Story LS Means Baby Diff Book Diff Color Diff Home Diff Pool Diff Twins Diff
BABY 62.20
BOOK 50.30 11.90COLOR 69.46 -7.26 -19.16
HOME 68.05 -5.85 -17.75 1.41
POOL 65.28 -3.08 -14.98 4.18 2.77
TWIN 67.03 -4.83 -16.73 2.43 1.02 -1.75
What about rate of growth?
Real interest in DORF passages is to estimate rate of skill acquisition
Typical Practice Test Students Every 2 Weeks Compute a best-fitting straight line through the
data Students with low rates are targeted for
intervention or adjustments to instruction
Descriptive Data over 4 Waves
WAVE BABY BOOK COLOR HOME POOL TWIN
1 M 74.33
SD 30.65
M 67.91
SD 31.18
M 89.41
SD 34.24
M 93.86
SD 36.91
M 85.65
SD 35.12
M 88.83
SD 32.84
2 M 107.95
SD 35.44
M 61.27
SD 33.13
M 97.33
SD 34.07
M 87.75
SD 33.82
M 77.96
SD 31.74
M 81.10
SD 33.67
3 M 93.89
SD 38.49
M 97.00
SD 38.34
M 83.00
SD 35.91
M 79.35
SD 29.61
M 71.14
SD 20.65
M 80.95
SD 28.94
4 M 87.11
SD 38.28
M 86.69
SD 41.26
M 88.19
SD 37.73
M 75.63
SD 27.92
M 105.58
SD 33.71
M 81.57
SD 26.57
Grand Mean
M 84.26
SD 35.63
M 73.68
SD 36.03
M 89.37
SD 34.85
M 86.65
SD 34.02
M 84.65
SD 33.46
M 85.02
SD 31.20
Grand
Mean
M 83.02
SD 34.47
M 83.81
SD 36.19
M 83.93
SD 32.91
M 86.81
SD 34.54
M 83.91
SD 34.48
Tests of Fixed Effects
EFFECTNUM
DFDEN DF
F VALUE
Pr > F
TPRI_FLUENCY(STORY) 5 224 137.8 <.0001WAVE 1 115 0.24 0.6239GROUP 5 110 3.27 0.0086WAVE*GROUP 5 115 3.47 0.0047
Estimated Growth Rates
LSMean Fluency by Wave and Group
Linear and Quadratic Trends by Group
Group Wave 1 Wave 2 Wave 3 Wave 4 Linear Quadratic
A Twin Color Baby Book Pool Home 2.23 4.44
B Color Baby Book Pool Home Twin 0.01 1.51
C Baby Book Pool Home Twin Color 1.08 -0.59
D Book Pool Home Twin Color Baby 0.09 0.49
E Pool Home Twin Color Baby Book -3.66 -3.54
F Home Twin Color Baby Book Pool -0.96 3.21
Conclusions
Conclusions
Form Effects in PM assessments must be addressed if teachers are to: Form valid inferences about student progress Target the right students for intervention and
supplemental instruction
The problem is not one of reliability in terms of low correlation between alternate forms
The problem is one of inconsistency in scaling across forms
Conclusions (cont.)
These form effects adversely affect the reliability and validity of slope estimates.
The problem is not unique to DIBELS, nor to CBM, but it has been ignored in this literature.
CBM was chosen for this study because of its popularity for PM assessment.
The CBM literature implies that fluency (WCPM) inherently provides a constant scale.
For WCPM to provide a constant scale, forms must be parallel
A more viable solution is to remove “form effects” through scaling of the raw ORF scores
We have to develop a scale score that takes “form difficulty” into account
One potential solution is equipercentile equating
Progress Monitoring
Solution is to empirically equate forms and develop a scale score metric that factors out form differences
Because of the large number of forms in use, we propose a “FEDEX” model that equates all forms to a single standard form based on percentiles