The University of North Carolina at Chapel Hill School of Social Work SOWO 916 Structural Equation Modeling Spring Semester, 2013 INSTRUCTOR Natasha K. Bowen, Ph.D. Room 245E, Tate Turner Kuralt Building CB #3550, School of Social Work, Chapel Hill, NC 27599-3550 Phone: (919) 843-2434 Email: nbowen@email.unc.edu CLASS MEETING TIMES & OFFICE HOURS Class meets on Wednesdays 9:00-11:50 am in TTK Room 102 Office hours are Wednesdays 12:00 – 1:00 or by appointment COURSE DESCRIPTION This course was originally developed by Dr. Shenyang Guo. We will use much of his syllabus, materials, and assignments throughout the semester. Structural equation modeling (SEM) is a general statistical method that can be employed to test theoretically derived models. It is “a class of methodologies that seeks to represent hypotheses about the means, variances, and covariances of observed data in terms of a smaller number of ‘structural’ parameters defined by a hypothesized underlying model” (Kaplan, 2000). In this course, students will learn fundamental concepts and skills to conduct SEM, and how to apply these techniques to social work research. COURSE OBJECTIVES At the completion of the course, students will be able to: Understand the fundamental hypothesis of SEM and its relationship to the specification, identification, and estimation of a structural equation model; Run path analysis and test mediating hypotheses using SEM; Conduct confirmatory factor analysis to evaluate measurement validity; Conduct structural equations with latent variables and apply the method to test/confirm a theoretically derived model; Understand statistical indices measuring goodness-of-fit of a model; Conduct multiple group comparisons with SEM to test moderating effects; Perform power analysis with SEM and know how to determine minimum sample size needed; Understand basic concepts and skills to deal with interactions and quadratics in latent variables, and categorical variables; Understand the linkage between SEM and hierarchical linear models, and conduct multilevel analysis and latent growth curve analysis with SEM; Understand strategies for dealing with missing data. PRE-REQUIREMENT Students are assumed to be familiar with descriptive and inferential statistics. A solid understanding of multiple regression analysis is a key. They should have statistical and statistical software background at least equivalent to that provided by SOWO919 (applied regression analysis and generalized linear models), SOCI209, PSYC282, EDUC284 (linear regression), or SOCI211 (categorical data analysis). SOFTWARE PACKAGES Students may choose to use SAS, SPSS, or Stata for data management and matrix calculations. Class examples in these areas will be in Stata. The course will employ Mplus for running SEM. Mplus is available through the university’s Virtual Computer Lab. Students are expected to use the Lab’s help resources to learn how to establish connections with the Lab. TEXTBOOKS Required: Bowen, N. K., & Guo, S. (2011). Structural Equation Modeling. New York, NY: Oxford University Press. Recommended for students who will be conducting SEM’s in their futures: Bollen, K. A. (1989). Structural equations with latent variables. New York, NY: John Wiley & Sons. Byrne, B. M. (2012). Structural equation modeling with Mplus. New York: Routledge. Hoyle, R. H. (Ed.). (2012). Handbook of structural equation modeling. New York: Guilford Press. Kline, R. (2011). Principles and Practice of Structural Equation Modeling, 3rd Ed., New York: NY: Guilford Press. ASSIGNMENTS 2 peer evaluations 5 IRATS 5 TRATS Team Application Activities 7 Homeworks GRADE PERCENTAGE 10% 15% 20% 20% 35% TOTAL 100% 2 GRADING SYSTEM The standard School of Social Work interpretation of grades and numerical scores will be used. H = 94-100 P = 80-93 L = 70-79 F = 69 and below POLICY ON CLASS ATTENDANCE Class attendance is critical for team performance and individual learning. You are expected to attend all scheduled sessions. Each class session will cover a great deal of material, and you will fall behind in the course when you miss even one class. In addition, your team will be disadvantaged by your absences. It is your responsibility to inform the instructor in advance about missing a class session. Starting after the second absence, your course grade will be reduced by 10% for each session missed. This reduction will occur after the calculation of your final grade and will be in addition to the effects absences may have on your peer evaluations. If you miss a class, you are responsible for obtaining all notes, announcements, handouts, and assignments from the missed class from your classmates. If you miss three classes, you will be expected to meet with the instructor and Associate Dean of Student Services to discuss if further participation in the course is possible. A grade of incomplete will only be given under extenuating circumstances and in accordance with University policy. POLICY ON INCOMPLETE AND LATE ASSIGNMENTS Assignments are to be turned in to the instructor at the beginning of class on the due date noted in the course outline if the class meets on a due date. If assignments are sent by email, do not assume they have been received until confirmation is received. Extensions may be granted by the professor given advance notice of at least 24 hours and extenuating circumstances. Unannounced late assignments will automatically be reduced 10%. An additional 10% grade reduction on the assignment will occur for each day late (including weekend days). A grade of incomplete will only be given under extenuating circumstances and in accordance with University policy. POLICY ON ACADEMIC DISHONESTY In-class activities are designed to create a collaborative learning environment. However, graded assignments are to be completed totally independently. Once an assignment has been handed out, it is assumed that students will not discuss any aspect of the assignment together—not even general principles or topics related to the assignment. Such exploring or sharing of knowledge that is even peripherally related to class assignments gives an unfair advantage to students who have peers from the same department or school enrolled in the course. Violations constitute violations of the honor code and will be treated as such. 3 Please include the honor code statement along with your signature on all assignments: “I have neither given nor received unauthorized aid on this assignment.” This statement indicates to the instructor that you did not consult with students or other human sources on any aspect of the assignment. It also represents your pledge that you have not made use of information or materials related to graded assignments from last year’s course. For assignments that are open book and take home (such as homeworks), consulting non-human sources (text and online sources) is encouraged. For example, you may read existing SEMNET postings, articles and Powerpoints about topics that are posted online, and book chapters, but you may not post a question related to an assignment to a discussion board. All questions about assignments and these policies should be referred to the instructor. Please refer to the APA Style Guide (6th edition), the SSW Manual, and the SSW Writing Guide for information on attribution of quotes, plagiarism and appropriate use of assistance in preparing assignments. If reason exists to believe that academic dishonesty has occurred, a referral will be made to the Office of the Student Attorney General for investigation and further action as required. POLICY ON ACCOMMODATIONS FOR STUDENTS WITH DISABILITIES Students with disabilities that affect their participation in the course and who wish to have special accommodations should contact the University’s Disabilities Services and provide documentation of their disability. Disabilities Services will notify the instructor that the student has a documented disability and may require accommodations. Students should discuss the specific accommodations they require (e.g. changes in instructional format, examination format) directly with the instructor immediately after the first class session and before the second class session. Retroactive accommodations will not be implemented. The instructor is happy to make any necessary accommodations to ensure optimal learning for every student. POLICIES ON THE USE OF ELECTRONIC DEVICES IN THE CLASSROOM We will discuss the use of laptops for in-class activities on the first day. The use of electronic devices for non-class related activities (e.g. checking messages, playing games) is prohibited. If any such uses occur during class time, laptops will not be allowed for any students for the remainder of the course. 4 DATES AND DESCRIPTIONS OF ASSESSMENTS AND HOMEWORK ASSIGNMENTS DATE 1/9 1/23 1/30 2/6 2/13 2/20 2/27 3//6 3/20 3/27 4/3 4/10 4/17 4/23 ASSIGNMENT DESCRIPTION ASSESSMENT 1 HOMEWORK 1 DUE HOMEWORK 2 DUE ASSESSMENT 2 HOMEWORK 3 DUE NO HW OR RAT! ASSESSMENT 3 HOMEWORK 4 DUE ASSESSMENT 4 HOMEWORK 5 DUE HOMEWORK 6 DUE ASSESSMENT 5 HOMEWORK 7 DUE Matrices, Intro to SEM Matrix algebra, basic statistics Path analysis with traditional regression Confirmatory factor analysis Running an Mplus CFA General structural models Running an Mplus general structural model SEM with ordinal and non-normal data Running Mplus with WLSMV Comparing analyses with Mplus’ clustered data options Latent growth modeling Running a Latent growth model in Mplus Homework assignments are due at the beginning of class and must include the student honor pledge (I have neither given nor received unauthorized assistance on this assignment) to be accepted. 5 OUTLINE OF COURSE TOPICS AND READINGS 1/9/13: Introduction to SEM and Underlying Statistics (class 1) 1. Intro to TBL 2. Intro to SEM Three types of SEMs Basic statistical concepts—IRAT, TRAT Path diagrams—Team Activity 5. Underlying hypothesis in SEM 1/16/13: No class—Read and study for next week 1/23/13: Matrices and Matrix Algebra (class 2) 1. Many kinds of matrices 2. Manipulation of matrices 3. SEM specification—Path Diagrams and Matrices Required readings and resources (recommended order, B & G, powerpoint, Bollen) Bollen (1989), Appendix A: Matrix Algebra Review (focus on types of matrices, major features of matrices, special matrices, and simple manipulations) Bowen & Guo Chapers 1 & 2, pp. 3-51 (you may pay less attention to the parts about equations) Matrices Powerpoint Recommended resources: Matrix operations review by Ender; Multivariate matrices; and matrix operations in Stata, SPSS, SAS by Ender (Ender’s pdf file on matrix algebra summarizes important matrix operations) RAT1 Homework 1 assigned 1/30/13: Path Analysis I (class 3) 1. Specification—Path diagrams, matrices, equations 2. Mediation 3. Identification 4. The concept of model fit Required readings: Bowen & Guo, Return to chapter 2 and read the sections about equations 6 Kline, R. (2005). Principles and practice of structural equation modeling, 2nd ed. New York, NY: Guilford Press. Chapter 5, pp. 93-122. (note: posted chapter goes beyond p. 122; you only need to print to p. 122) Homework 1 due at the beginning of class Homework 2 assigned 2/6/13: Path Analysis II (class 4) 1. Path analysis estimation in Mplus 2. More on the evaluation of fit (χ2) 3. Evaluation of parameters 4. Direct, indirect and total effects Required readings: (recommended order—alphabetical) Bowen & Guo, pp. 141 and 144 in Chapter 6 (on χ2) Kline, R. (2005). Principles and practice of structural equation modeling, 2nd ed. New York, NY: Guilford Press. Chapter 6, pp. 123-164. Wu, Hui-ching (2011). The protective effects of resilience and hope on quality of life of the families coping with the criminal traumatisation of its [sic] members. Journal of Clinical Nursing, 20, 1906-1915. Available online at: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2702.2010.03664.x/pdf Homework 2 due at the beginning of class 2/13/13: SEM with latent variables: Confirmatory Factor Analysis (class 5) 1. Latent variables 2. Theory 3. Specification—path diagram, matrices, equations 4. Identification 5. More on model fit Required readings (recommendation: read B&G, then Bollen): Bollen, K. A. (2000). Modeling strategies: In search of the Holy Grail. Structural Equation Modeling 7, 74-81. Bowen & Guo, Chapter 4, pp. 73-108; and pp. 141-144 on χ2 in Chapter 6. CFA Powerpoint An optional (user-friendly) reading: Iacobucci, D. (2009). Everything you always wanted to know about SEM but were afraid to ask. Journal of Consumer Psychology, 19, 673-680. RAT2 Homework 3 assigned 7 2/20/13: Confirmatory Factor Analysis: A closer look (class 6) 1. Alternative models 2. Second-order CFA models 3. Correlated measurement errors 4. Improving and comparing models--Intro Required readings: Bentler P. M. & Mooijaart, A. (1989). Choice of structural model via parsimony: A rationale based on precision. Psychological Bulletin, 106, 315-317. Bowen & Guo, Chapter 6, pp. 135-166 (some parts are review) Gerbing, D. W. & Anderson, J. C. (1984). On the meaning of within-factor correlated measurement errors. Journal of Consumer Research, II, 572-580. Homework 3 due at the beginning of class Midterm course feedback 2/27/13: Confirmatory Factor Analysis in Scale Development (class 7) 1. Theory 2. Validity 3. Reliability 4. MIMIC models 5. Method effects and Multi-method multi-trait models Required readings: Eid, M., Nussbeck, F. W., Geiser, C., Gollwitzer, M., Cole, D. A., & Lischetzke, T. (2008). Structural equation modeling of multitrait-multimethod data: Different models for different types of methods. Psychological Methods, 13, 230-253. Gregory, Jr., V. L. (2012). Gregory Research Beliefs Scale: Discriminant construct, concurrent criterion, and known-groups validity. Journal of Evidence-Based Social Work, 9, 465-480. Pohl, S., & Steyer, R. (2012). Modeling traits and method effects as latent variables. In S. Salzborn, Davidov, E., & Reinecke, J. (eds.). Methods, theories, and empirical applications in the social sciences. Wiesbaden, Germany: Springer. Reliability article TBA Midterm peer evaluations 3/6/13: General SEM: Structural and measurement models combined (class 8) 1. Theory 2. Specification-- path diagram, matrices, equations 3. Identification 8 4. Estimation 5. Improving models Required readings: Anderson, J. C. and D. W. Gerbing (1988). Structural equation modeling in practice A review and recommended two-step approach. Psychological Bulletin 103, 411-423. Bowen & Guo, chapter 5, pp. 109-134 and review chapter 6, pp. 157-166. Ferron, J. M. and M. R. Hess (2007). Estimation in SEM: A concrete example. Journal of Educational and Behavioral Statistics, 32: 110-120. Rothbard, N. P. (2001). Enriching or depleting? The dynamics of engagement in work and family roles. Administrative Science Quarterly, 46, 655-684. RAT3 Homework 4 assigned 3/13/12: HAVE A GOOD SPRING BREAK! 3/20/12: Multiple Group Modeling (class 9) 1. Path analysis 2. CFA 3. General structural models Required readings: Bowen & Guo, review Chapter 6, 149-157 and Chapter 7, pp. 180-186 Dimitrov, D. M. (2010). Testing for factorial invariance in the context of construct validation. Measurement and Evaluation in Counseling and Development, 43, 121-149. Simons, R. L., Johnson, C., Beaman, J., Conger, R. D., and Whitbeck, L. B. (1996). Parents and peer group as mediators of the effect of community structure on adolescent problem behavior. American Journal of community Psychology, 24, 145-171. Werner, C. & Schermelleh-Engel. (2010). Deciding between competing models: Chi-square difference tests. Available at: http://user.uni-frankfurt.de/~cswerner/sem/chisquare_diff_en.pdf Recommended: Cheung, G. W. & Rensvold, R. B. (2002). Evaluating goodness-of-fit indexes for testing measurement invariance. Structural equation modeling, 9, 233-255. Homework 4 due at the beginning of class 9 3/27/12: Appropriate SEM Approaches for Social Science Data I (class 10) 1. Robust Estimators for Non-Normal Measures 2. What to do With Ordinal Data 3. A note on multiple group analysis with WLSMV Required readings: Bowen & Guo, pp. 57-65 in Chapter 2 Flora, D. B., & Curran, P. J. (2004). An empirical evaluation of alternative methods of estimation for confirmatory factor analysis with ordinal data. Psychological Methods, 9(4), 466-491. Sass, D. A. (2011). Testing measurement invariance and comparing latent factor means within a confirmatory factor analysis framework. Journal of Psychoeducational Assessment, 29, 347-363. Wegmann, K. M., Thompson, A. M., & Bowen, N. K. (2010). A confirmatory factor analysis of home environment and home social behavior data from the ESSP for Families. Social Work Research, 35, 65-128. RAT4 Homework 5 assigned 4/3/12: Appropriate SEM Approaches for Social Science Data II (class 11) 1. Missing Data 2. Clustered Data 3. Power Required readings: Bowen & Guo, Chapter 3, pp. 52-72 Bowen & Guo Chapter 7, sections on power analysis and the problem of underidentification, pp. 167-179 MacCallum, R.C., Browne, M.W., & Sugawara, H.M. (1996). Power analysis and determination of sample size for covariance structure modeling, Psychological Methods 1, 130-149. Enders, C. K., & Bandalos, D. L. (2001). The relative performance of full information maximum likelihood estimation for missing data in structural equation models. Structural Equation Modeling, 8, 430-457. Homework 5 due at the beginning of class Homework 6 assigned 10 4/10/13: Longitudinal Analyses in SEM--ARCL (class 12) 1. Autoregressive, cross-lagged models 2. Specification 3. Identification Required readings: Cole, D. A. & Maxwell, S. E. (2003). Testing meditational models with longitudinal data: Questions and tips in the use of structural equation modeling. Journal of Abnormal Psychology, 112, 558-577. Homework 6 due at the beginning of class 4/17/13: Longitudinal Analyses in SEM--Latent growth models (class 13) Required readings: Curran, P. J., & Willoughby, M. T. (2003). Implications of latent trajectory models for the study of developmental psychopathology. Development and Psychopathology, 15. 581-612. Latent growth modeling Powerpoint RAT5 Homework 7 assigned 4/23/13: Follow-up, Catch-up, Wrap-up Homework 7 due at the beginning of class 11