The Causeor the What of What Works

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The Causeor the What of What Works?

• David S. Cordray
• Vanderbilt University
• IES Research Conference
• Washington, DC
• June 16, 2006

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Expected Relative Strength .25
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Intervention Fidelity
Intervention, as conceptualized (T and C)
Does the intervention, as implemented, faithfully
represents the intervention theory or model?
Intervention, as realized or implemented (t and
c)
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Dimensions Intervention Fidelity

• Adherence to the intervention model
• Essential components (activities, processes)
• Necessary, but not unique, activities, processes
  and structures (supporting the essential
  components of T)
• Ordinary features of the setting (shared with C)
• Quality of delivery (adherence) and
• Receipt essential components.

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Fidelity and IES Goals

• Goal 2 (Development)
• Need explicit model of the final intervention
  model
• Products
• Evidence of potential effects,
• an intervention model,
• all relevant materials, and
• detailed indices for assessing fidelity
• Goals 3 (Efficacy) and 4 (Scale-up)
• Need detailed indices of fidelity for
• training and program research (e.g., effects of
  core components) and
• Need efficient indices for scaling implementation
  in the unit of delivery
• Need efficient indices of fidelity in all
  conditions (T and C)
• Goal 6 Managing the tension between fidelity
  and inevitable adaptation

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Substantial Challenges

• Developing explicit enough program models so the
  fidelity can be meaningfully assessed
• Measuring fidelity entails
• Multiple indicators
• Mixed methods
• Constructing indexes
• Differential weighting of components
• Use of broader range of scale construction
  procedures (cumulative and rubric-based)
• Validation studies
• Because fidelity plays many roles, well need
  multiple versions of fidelity scales (e.g,
  scale-down)

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The Causeand What Works?

• In experimental research, the causal agent is a
  relative difference between ingredients in T and
  C conditions
• The achieved relative strength of the contrast is
  affected by infidelity and
• With adequate indices of fidelity, we can move to
  questions of what works, under what
  circumstances, and why.