Graphing and Single Subject Designs

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Graphing and Single Subject Designs

• Lecture Notes for September 8
• SPEC 3020
• Fall 2009
• http//coefaculty.valdosta.edu/pgunter/SPEC3020/in
  dex.htm

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Three Purposes of Graphs

• Means for Organizing Data during the data
  collection process
• The Ongoing Picture Makes Possible Formative
  Evaluation
• Serve as a Vehicle for Communication

3
The Graphic Display

• Single Subject Design Researchers rely on Visual
  Inspection

4
Use of Microsoft Excel to Develop Single-Subject
Design Graphs (Carr and Burkholder, 1998)

• Example
• Sarahs Multiple Baseline

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Participants Graph Their Own Data

• See Schloss
• See Gunter
• See Figirola
• See Sutherland

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Variables and Functional Relationships

• Variable
• Dependent variable ( the beauty of rate )
• Independent variable
• Functional relationship -- When changes in the
  dependent variable are replicated each time the
  same independent variable is implemented
• (Single-subject designs provide the framework
  within which to test for the replications of
  effect)

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Baseline Measures

• Descriptive Function
• Predictive Function
• Stability
• Variability 5 20 50
• Trend
• Ascending
• Descending

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Visual Analysis

• Characteristics of data paths
• Mean
• Level
• Trend
• Percentage of Overlap
• Rapidity

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Trend

• Visual
• Quarter-Intersect Method (Line of Progress)
• Draw a vertical line dividing the data
• Divide the data on the left half with a vertical
  line and divide the data on the right half with a
  vertical line
• Find the mid-performance point (half the data
  fall above and half fall below) for the right
  half and left half
• Connect the intersetion of both halves of the
  data
• See page 161 and 162 of Text

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Designs

• AB Design
• ABAB Design (Reversal Design)
• Alternating Treatments Design (Concurrent
  Treatments Design)
• Changing Conditions Design
• Changing Criterion Design
• Multiple Baseline Design
• Multiple Probe Design

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AB Design

• Advantages Simple
• Disadvantage Can not make confident
  assumption regarding a functional
  relationship
• Seldom found in research literature

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ABAB Design (Reversal)

• Advantages Simplicity, experimental
  control
• Disadvantage Withdrawing an effective
  intervention

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Multiple Baseline Design

• Advantage Permits simultaneous analysis
  of more than one dependent variable
  across behaviors, across settings,
  across individuals
• Disadvantage Requires extended baseline
  evaluation

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Multiple Probe

• Eliminates the necessity of recording extended
  baseline conditions in multiple baseline designs.

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Alternating Treatments

• Advantages Allows comparison of more than
  one intervention (or independent
  variable)

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• Article Examples
• Data Collection System
• Design