Thesis (M.A.)--University of Notre Dame, 2009. / Thesis directed by Scott E. Maxwell for the Department of Psychology. "November 2009." Includes bibliographical references (leaves 105-107).

It is possible to quantify and understand how an exposure affects an outcome through an intermediate variable via causal mediation analysis. In many cases in practice, however, the effect of the exposure may vary for different subgroups of the population. Combining these two ideas results in the related concepts of moderated mediation and mediated moderation. Addressing questions of why and how an exposure gives rise to an outcome differently for different subsets of the population provides deeper understandings of the effect heterogeneity phenomenon and permits insights that may be both clinically and practically meaningful about what works for whom and through which intermediate(s).This dissertation explores how to understand and explain these causal mechanisms by focusing on explaining effect heterogeneity via causal mediation analysis. Formal definitions and analytical formulas for direct and indirect effect heterogeneity measures are described from a counterfactual perspective. Various types of direct and indirect effect heterogeneity from two-way and three-way decompositions, such as natural direct and indirect effect heterogeneity and pure direct and indirect effect heterogeneity, are introduced and defined. However, just simply decomposing the total effect heterogeneity into direct and indirect effect heterogeneity does not fully account for the complex mechanism of the two-way and three-way interactions happening in the effect heterogeneity phenomenon. Arising from this, in the context of a regression-based approach, this dissertation shows how direct and indirect effect heterogeneity can be further decomposed to account for possible multi-way interactions between exposure, mediator, and modifier. This is an essential way to account for different portions of interactions along causal pathways of effect heterogeneity. It provides more causal implications about the question for whom and in what context that the effect happens. Identification assumptions that are sufficient for the estimations of effect heterogeneity decompositions are also considered. Analytical expressions for effect heterogeneity decompositions on additive and ratio scales are provided. National Longitudinal Study of Adolescent to Adult Health (Add Health) data is used to illustrate the proposed methodologies in application.

Thesis (Ph. D.)--University of Notre Dame, 2009. / Thesis directed by Ke-Hai Yuan for the Department of Psychology. "July 2009." Includes bibliographical references (leaves 151-155).

中介效應和調節效應分析在心理學研究中廣泛存在。調節效應發生時，自變量和因變量的關係的強度或方向會因調節變量的水平而有所改變。另一方面，中介效應發生時，自變量會通過中介變量對因變量來產生影響(Baron& Kenny,1986) 。心理學家經常結合這兩種效應以處理更複雜的問題，例如:調節作用是如何發生或中介作用在什麼情況會有所改變。研究學者定義前者為有中介的調節作用，後者為有調節的中介作用。儘管在文獻中有許多關於中介的調節效應和有調節的中介效應的分析方法的討論，對於理解這兩種效應的混亂仍然存在。此外，結構方程模型分析方法雖然比傳統的迴歸分析方法更靈活和有效地處理這兩種效應的分析，但是文獻上卻甚少討論如何應用結構方程模型於有中介的調節作用和有調節的中介作用的分析上。本論文回應以上提出的問題，主要討論如何把結構方程模型的分析方法應用在有中介的調節效應和有調節的中介效應的分析上，論文的第一部份會透過闡明五種常見有關於有中介的調節效應和有調節的中介效應的概念模型以消除研究橕者對這兩種效應定義的誤解。在論文的第二部分將會提出一個用以轉換有中介的調節效應和有調節的中分效應的概念模型為能應用於結構方程模型分析法上的模型的統一方法，讓研究學者能統一方法中提出的規則簡易地把假設模型變成為可為結構方程模型作分析的模型。模擬實驗來比較迴歸方法和結構方程模型方法的實際效用。結果顯示，這兩種分析方法發現相近。論文最後的部份，引人用於潛變量調節作用分析上的unconstrained indicant product approach (Marsh et al., 2004) ，並結合本文提出的統一方法來分析有中介的調節作用和有調節的中介作用，模擬實驗結果顯示這種方法在大多數的模擬情況下表現令人滿意。然而，以評估模型擬合度的卡方檢定在模擬實驗的大多數情況中都並不準確，因此研究學者應謹慎處理卡方檢定。 / Moderation and mediation analyses are widespread in psychological research. Moderation occurs when the direction and/or strength of the relation between an independent variable and a dependent variable depends on the level of a moderating variable. Mediation, on the other hand, occurs when the effect of an independent variable on a dependent variable is transmitted through a mediating variable (Baron & Kenny, 1986). Psychologists often move beyond these two processes and ask more complex questions such as how a moderating effect takes place or when a mediating process varies in different contexts. The former question has been referred as mediated moderation while the latter one has been referred as moderated mediation. Despite the fact that there are many discussions about the analysis of mediated moderation and moderated mediation in the literature, the confusion over the interpretation of these two processes persists. In addition, the SEM method, which is known to be more flexible than traditional egression method for the analysis of mediated moderation and moderated mediation is rarely discussed in the literature. In response to these issues, the main objective of the present study was to examine the methods for the analysis of mediated moderation and moderated mediation in the SEM framework. The first part of this study resolved the confusion over the current interpretation of the mediated moderation and moderated mediation by demonstrating these two processes using five typical conceptual models of mediatedmoderation and moderated mediation. In the second part, a new unified method was proposed to provide some general rules for translating the conceptual models of mediated moderation and moderated mediation into the SEM working models. The empirical performance of SEM analysis against regression analysis was assessed by a simulation study. Results showed the two methods performed similarly across different model conditions. In the last part, the unconstrained indicant product approach (Marsh, et al., 2004) for latent moderation analysis was introduced and combined with the unified approach for the analysis of latent variable mediated moderation and moderated mediation models. Simulation findings suggested that this method performed satisfactorily for testing mediated moderating and moderated mediating effects in most simulation conditions. However, chi-square statistics for the evaluation of model fit should be used with cautious as simulation results indicated that they were not accurate in most cases. / Detailed summary in vernacular field only. / Kwan, Lok Yin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 104-114). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / ACKNOWLEDGEMENT --- p.iii / ABSTRACT --- p.v / CHINESE ABSTRACT --- p.vii / TABLE OF CONTENTS --- p.ix / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Moderation --- p.2 / Mediation --- p.2 / Moving Beyond Moderation and Mediation --- p.4 / Objectives of This Study --- p.6 / Outline of the Following Chapters --- p.8 / Chapter CHAPTER 2 --- MEDIATED MODERATION AND MODERATED MEDIATION --- p.10 / Mediated Moderation --- p.11 / Moderated Mediation --- p.13 / Critical Issues Related to the Current Interpretations --- p.14 / Moderated Mediation within a Mediation Context --- p.19 / Mediated Moderation within a Moderation Context --- p.21 / Summary of This Chapter --- p.25 / Chapter CHAPTER 3 --- ANALYSIS OF MEDIATED MODERATION AND MODERATED MEDIATION --- p.27 / Models --- p.27 / Regression-based Methods --- p.33 / Structural Equation Modeling Approach --- p.39 / A Unified Approach for Model Specification in SEM --- p.42 / Regression-based Method Versus SEM Approach --- p.49 / Chapter CHAPTER 4 --- SIMULATION STUDY 1: REGRESSION-BASED VERSUS SEM-BASED METHODS --- p.51 / Design of the Simulation Study --- p.51 / Procedure --- p.54 / Results --- p.55 / Discussion and Conclusion --- p.63 / Chapter CHAPTER 5 --- LATENT VARIABLES MEDIATED MODERATION AND MODERATED MEDATION --- p.68 / Unconstrained Indicant Product Approach --- p.69 / Model Specifications of Latent meMO and moME Models --- p.76 / Simulation Study 2: Methods --- p.83 / Simulation Study 2: Results --- p..88 / Discussion and Conclusion --- p.94 / Chapter CHAPTER 6 --- CONCLUSION AND FUTURE DIRECTION --- p.97 / Practical Significance of This Study --- p.98 / Limitations and Future Direction --- p.99 / REFERENCES --- p.104 / ENDNOTES --- p.115 / LIST OF TABLES --- p.117 / TABLES --- p.119 / FIGURE CAPTION --- p.153 / FIGURES --- p.154

The purpose of this study was to examine the effectiveness and exposure of an implementation strategy, which included a 4-day in-class training with two follow-up technical assistance calls, on mediating factors hypothesized to be positively associated with staff’s intention to use a five-session, couples-based HIV and other sexually transmitted prevention intervention. The Consolidated Framework for Implementation Research (CFIR) guided the study aims and analysis of the direct effect of exposure to the implementation strategy and 3 factors hypothesized to mediate the implementation strategies’ effect on intention to implement a couples-based intervention. Individual staff characteristics and an organizational process variable informed by Social Cognitive Theory (SCT), the Diffusion of Innovation Theory and Theory of Planned Action were examined. Two hundred and fifty-three staff, predominantly African American and Latina, from 80 organizations, were recruited from HIV service agencies, clinics and community-based organization from New York City and other regions of New York State. They were randomized by agency to either a multimedia condition or a traditional paper-based version of the couples-based intervention and received the implementation strategy 4-day, in-class intervention training followed by a technical assistance phone call at 3 and 6-months post training. Findings suggest that greater exposure to the implementation strategy in days and contacts was significantly associated with an increase in staff’s intention to implement the intervention at six months. Further, while a statistically significant effect of the implementation strategy dose on the mediators examined was not detected, the implementer’s experience of these mediators defined as self-efficacy for couples-based implementation, positive perception of the intervention’s characteristics and the perceived availability of an organizational intervention Champion was found to be significantly associated with the outcome variable intention to implement, and also was found to reduce the dosage effect of the implementation strategy on intention. Further examination of the implementation strategy’s content and dosage is needed to identify how increased intention to utilize an intervention at 6 months and 12 months following training and technical assistance may be enhanced through greater attention to and measurement of these mediators in addition to the implementation strategy dosage effect. Of note, the dosage effect on intention was found to diminish at the 12 month follow-up period suggesting the importance of timely support and planning prior to and post implementation strategies to increase utilization of an innovation. Implications for HIV prevention theory, and social work research, practice and policy are discussed.