Experimental Studies Heppner et al. (2015) Chap20 Class 3 Experimental Studies Heppner et al. (2015) Chap20

Psychology’s History of Being Mesmerized

Placebo Effect https://www.youtube.com/watch?v=HqGSeFOUsLI In 2002, researchers at the Houston VA Medical Center and at Baylor College of Medicine found that a common type of knee surgery known as debridement to be no more beneficial than a placebo surgery. Throughout a two year follow-up, the 180 patients in the study were unaware whether they had received the "real" or placebo surgery. Patients who received actual surgical treatments did not report less pain or exhibit better functioning of their knees compared to the placebo group.

Experimental Between Group Designs Post-Test Only Control Pre-Test -- Post-Test Control Solomon Four Group (combination of 1 and 2 above) Factorial Design more than one independent variable; interactions gender x treatment Dependent Sample Design (Matching) 4

Experimental Between Group Designs Post-Test Only Control Pre-Test -- Post-Test Control Solomon Four Group Factorial Design (e.g., Treatment X Therapist) Dependent Sample Design (Matching) # of previous episodes and severity depression, gender, marital status 5

Between Group Design Factorial Design: More than one IV Experimental AlI IVs are manipulated Ex Post Facto: All IVs are status variable (not manipulated)

Between Group Designs: Therapy Outcome Treatment Package Strategy Dismantling Strategy Additive Strategy Parametric Strategy Comparative Outcome Strategy Common Factors Control Group Design -- Placebo Moderation Designs

Cultural Modifications PCIT- GANA Assessment of culturally influenced concepts at intake and continuously to individualize treatment Framed program as educational/skill-bdng, vs therapy Parent Child Interaction Therapy to GANA Guiando Ninos Activos Engagement protocol for fathers and extended family Orientation/preparation for treatment – manage expectations Increased attention to rapport building – longer sessions Eliciting feedback – complaints “simpatia” script Translation and simplification of handouts- represent Hispanics in pictures

Types Between Group Designs Treatment Package Strategy Dismantling Strategy Additive Strategy Parametric Strategy (structural components)

Types Between Group Designs Treatment Package Strategy Compared PCIT – GANA - TAU Dismantling Strategy Additive Strategy Parametric Strategy (structural components)

Types Between Group Designs Treatment Package Strategy Compared PCIT – GANA - TAU Dismantling Strategy components of the same treatment Additive Strategy Parametric Strategy (structural components)

Types Between Group Designs Treatment Package Strategy Compared PCIT – GANA - TAU Dismantling Strategy components of the same treatment Additive Strategy Added new components (e.g. cultural evaluation: engagement protocol) Parametric Strategy (structural components)

Types Between Group Designs Treatment Package Strategy Compared PCIT – GANA - TAU Dismantling Strategy components of the same treatment Additive Strategy Added new components (e.g. cultural evaluation: engagement protocol) Parametric Strategy (structural components) (e.g. longer sessions for rapport bdng.)

Types Between Group Designs Comparative Outcome Strategy Common Factors Control Group Design -- Placebo Moderation Designs Client /therapist characteristics

Types Between Group Designs Comparative Outcome Strategy Common Factors Control Group Design -- Placebo Moderation Designs Client /therapist characteristics

Types Between Group Designs Comparative Outcome Strategy Compared PCIT- GANA-TAU Common Factors Control Group Design -- Placebo Moderation Designs Client /therapist characteristics

Types Between Group Designs Treatment Package Strategy Dismantling Strategy Additive Strategy Parametric Strategy Comparative Outcome Strategy Common Factors Control Group Design -- Placebo Moderation Designs

Dismantling vs. Package Strategies Identify change mechanisms Do specific ingredients work as expected? VS. How well the treatment works

Dismantling Strategy: How Treatment Effects Change Effectiveness of (Jacobson et al. 1996): BA ------- BA + AT ------- BA + AT + CT Component Measure Ttreat. Group Behavioral activation – Pleasant Event SCd BA Coping skills- - AT (Dist Thinking) AT Core schemas - Exp Attrb Style CT Change from pre-to post- treatment in depression and in each change mechanism

Which group to use in outcome analyses ? # Sessions Intent-to treat Total sample n = 58 (pre-test) Partial completers 5+ Sessions n = 44 Completers Full treatment n = 33 57% Post-treatment assessment n = 54 93%

Table 2 Self Report Measures

Cohen’s d – effect size 0.2 small 0.5 medium 0.8 large If two groups' means don't differ by 0.2 standard deviations or more, the difference is trivial, even if it is statistically significant.

Table 3 – Observational Measures

Significance Statistically Significant Findings Clinically Significant Findings

Significance Statistically Significant Findings Clinically Significant Findings behavior problems (ECBI) and externalizing symptoms (CBCL) GANA /PCIT- below normative mean TAU below clinical mean

External and Internal Validity E I Experimental Field E i Correlational/ Descriptive e I Laboratory e i

External and Internal Validity E I Experimental Field E i Correlational/ Descriptive e I Laboratory e i Clinical Trials