Treatment Efficacy - Eppp Knowledge

1. Which option best indicates a clinically meaningful change rather than only statistical significance?

   Reliable and clinically significant change (RCI plus normative cutoff). This metric combines statistical reliability with real-world functionality to assess meaningful patient improvement.

2. What is the primary comparative advantage of meta-analysis over a single RCT?

   Aggregates effects across studies to estimate overall effect more precisely. Meta-analysis synthesizes multiple studies, reducing random error and yielding a more reliable overall effect estimate.

3. Which validity threat occurs when differential dropout biases comparative treatment outcomes?

   Attrition (mortality) threat to internal validity. Attrition threatens validity when unequal dropout rates create non-equivalent groups, confounding outcome comparisons.

4. What is the formula for Cohen's $d$ for two independent groups?

   $d=\frac{M_1-M_2}{SD_{pooled}}$. Cohen's $d$ quantifies the standardized mean difference between groups, facilitating effect size comparisons.

5. Which research design provides the strongest evidence for comparative treatment efficacy?

   Randomized controlled trial (RCT). RCTs minimize bias through randomization and controls, providing robust causal evidence for treatment differences.

6. What does a noninferiority trial primarily test when comparing two active treatments?

   That the new treatment is not worse than the standard by a preset margin. Noninferiority trials establish that a new treatment performs at least as well as the existing standard within an acceptable margin.

7. What is a dismantling study designed to determine when comparing treatment components?

   Which components are necessary or active ingredients. Dismantling studies isolate specific elements of a treatment to identify which contribute to therapeutic outcomes.

8. Identify the term for improvement due to natural symptom fluctuation toward the mean.

   Regression to the mean. Regression to the mean accounts for spontaneous improvements as extreme scores naturally revert toward average levels.

9. What does treatment fidelity (therapist adherence/competence) primarily protect against?

   Confounding due to inconsistent delivery of the intervention. Fidelity ensures consistent intervention application, minimizing variability that could obscure true treatment effects.

10. What is the most appropriate conclusion if two treatments have statistically equal outcomes but one is cheaper?

    Prefer the less costly option (greater cost-effectiveness). Cost-effectiveness prioritizes resource efficiency when clinical benefits are equivalent, optimizing healthcare allocation.

11. What is the key distinction between treatment efficacy and treatment effectiveness?

    Efficacy: controlled trials; effectiveness: real-world clinical settings. Efficacy evaluates treatments under ideal, controlled conditions, while effectiveness assesses them in typical practice environments with diverse patients.

12. What is an additive (component) study designed to test when evaluating a treatment package?

    Whether adding a component improves outcomes beyond the base treatment. Additive studies examine if incorporating an extra element enhances the efficacy of an established intervention.

13. Which control condition best addresses placebo effects in psychotherapy efficacy research?

    Attention placebo (nonspecific factors) control. Attention placebo controls equate nonspecific elements like time and expectation to isolate specific therapeutic mechanisms.

14. What is the formula for number needed to treat (NNT) using absolute risk reduction (ARR)?

    $NNT=\frac{1}{ARR}$. NNT is derived from ARR to indicate treatment efficiency in producing additional positive results.

15. Which concept explains why bona fide psychotherapies often show small differences in outcomes?

    Common factors (e.g., alliance, expectancy) contribute substantially. Common factors theory posits that shared elements across therapies drive much of the observed equivalence in efficacy.

16. Which bias occurs when studies with null treatment effects are less likely to be published?

    Publication bias (file drawer problem). Publication bias inflates apparent treatment effects by underrepresenting non-significant findings in the literature.

17. Which study feature most directly increases external validity for treatment effectiveness?

    Broad inclusion criteria in a naturalistic clinical setting. Broad, naturalistic criteria enhance generalizability by mirroring real-world patient diversity and conditions.

18. What does a larger Cohen's $d$ indicate when comparing treatment outcomes?

    Greater standardized difference between groups. A larger Cohen's $d$ reflects a more substantial treatment impact, indicating stronger separation in group outcomes.

19. What does the number needed to treat (NNT) represent in comparative effectiveness?

    Patients needed to treat to produce 1 additional favorable outcome. NNT translates absolute risk reduction into a practical metric for clinical decision-making across treatments.

20. Which treatment research finding most supports comparative superiority: $p<.05$ or larger effect size?

    Larger effect size (magnitude), not $p$ value alone. Effect size measures practical impact magnitude, providing stronger evidence of superiority than significance alone.

21. Which outcome metric best supports comparing interventions across different symptom scales?

    Standardized effect size (e.g., Cohen's $d$). Standardized metrics like Cohen's $d$ normalize outcomes, enabling direct comparisons despite varying measurement tools.

22. Which option best supports choosing a treatment for a diverse community clinic: efficacy or effectiveness evidence?

    Effectiveness evidence. Effectiveness studies provide pragmatic evidence for real-world applicability in varied, non-controlled settings.

23. Identify the term for comparing treatments by randomizing clinics rather than individuals.

    Cluster randomized trial. Cluster trials randomize groups to account for intra-cluster correlations, suitable for community or organizational interventions.

24. What does the reliable change index (RCI) primarily assess for an individual patient?

    Whether change exceeds measurement error. RCI determines if observed changes surpass expected variability from measurement imprecision in individual cases.

25. Which analysis strategy best preserves randomization when participants drop out of treatment?

    Intention-to-treat (ITT) analysis. ITT includes all randomized participants, reducing bias from non-compliance and maintaining group equivalence.

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