Adrian Tomer

Structural Equation Modeling: Applications in ecological and evolutionary biology

Part I. Theory: 1. Structural equation modelling: an introduction Scott L. Hershberger, George A. Marcoulides and Makeba M. Parramore 2. Concepts of structural equation modelling in biological research Bruce H. Pugesek 3. Modelling a complex conceptual theory of population change in the Shiras moose: history and recasting as a structural equation model Bruce H. Pugesek 4. A short history of structural equation models Adrian Tomer 5. Guidelines for the implementation and publication of structural equation models Adrian Tomer and Bruce H. Pugesek Part II. Applications: 6. Modelling intra-individual variability and change in bio-behavioural developmental processes Patricia H. Hawley and Todd D. Little 7. Examining the relationship between environmental variables and ordination axes using latent variables and structural equation modelling James B. Grace 8. From biological hypotheses to structural equation models: the imperfection of causal translation Bill Shipley 9. Analysing dynamic systems: a comparison of structural equation modelling and system dynamics modelling Peter S. Hovmand 10. Estimating analysis of variance models as structural equation models Michael J. Rovine and Peter C. M. Molenaar 11. Comparing groups using structural equations James B. Grace 12. Modelling means in latent variable models of natural selection Bruce H. Pugesek 13. Modeling manifest variables in longitudinal designs - a two-stage approach Bret E. Fuller, Alexander von Eye Philip K. Wood and Bobby D. Keeland Part III. Computing: 14. A comparison of the SEM software packages Amos, EQS and LISREL Alexander von Eye and Bret E. Fuller Index.This chapter provides an introduction to structural equation modeling (SEM), a statistical technique that allows scientists and researchers to quantify and test scientific theories. As an example, a model from behavioral genetics is examined, in which genetic and environmental influences on a trait are determined. The many procedures and considerations involved in SEM are outlined and described, including defining and specifying a model diagrammatically and algebraically, determining the identification status of the model, estimating the model parameters, assessing the fit of the model to the data, and respecifying the model to achieve a better fit to the data. Since behavioral genetic models typically require family members of differing genetic relatedness, multisample SEM is introduced. All of the steps involved in evaluating the behavioral genetic model are accomplished with the assistance of LISREL, a popular software program used in SEM.

Toward a comprehensive model of death anxiety

An integrative, comprehensive model of death anxiety is presented. The model postulates three immediate antecedents of death anxiety: past-related regret, future-related regret, and meaningfulness of death. Past-related regret refers to a persons unfulfilled aspirations that should have been achieved but were not. Future-related regret refers to the anticipation that, as a result of premature death, one cannot achieve important goals in the future. Meaningfulness of death refers to ones concept of death and ability to make sense of it. These three antecedents are related to death salience in a complex way, mediated by coping mechanisms and their effects on ones beliefs about self and the world. The coping mechanisms include (but are not necessarily limited to) life review, life planning, identification with culture, and self-transcending processes. The models developmental and practical applications are explored.

Beyond Terror and Denial: The Positive Psychology of Death Acceptance

Death remains the biggest threat as well as the greatest challenge to humanity. It is the single universal event that affects all of us in ways more than we care to know (Greenberg, Koole, & Pyszczynski, 2004; Wass & Neimeyer, 1995; Yalom, 2008). Because of the unique human capacity of meaning-making and social construction, death has evolved into a very complex and dynamic system, involving biological, psychological, spiritual, societal, and cultural components (Kastenbaum, 2000). Whatever meanings we attach to death may have important implications for our wellbeing. Thus, at a personal level, death attitudes matter: Death defines personal meaning and determines how we live (Neimeyer, 2005; Tomer, 2000; Tomer, Eliason, & Wong, 2008). At the cultural level, death also makes its ubiquitous presence felt in a broad spectrum of social functions, from family, religion, and the entertainment industry to medical care (Kearl, 1989). How we relate to our own mortality is in turn mediated by family, society, and culture (Kastenbaum, 2000). In sum, all human activities are framed by death anxiety and colored by our collective and individual efforts to resolve this inescapable and intractable existential given. In the post-9=11 era, the ever-present threat of terrorist attacks has injected into our collective awareness the unpredictable nature

Confronting Suffering and Death at the End of Life: The Impact of Religiosity, Psychosocial Factors, and Life Regret among Hospice Patients.

Although the role of spiritual, psychological, and social factors is receiving increasing attention in the end of life (EOL) context, we know far less than we need to about how these factors shape attitudes toward life and death in the face of looming loss. The present study begins to remedy these limitations by examining the relative impact of demographic characteristics, religious and psychosocial factors, and life regret on death attitudes and psychological well-being for a diverse group of 153 hospice patients. In addition to relying on well-validated quantitative assessments, qualitative interviews were conducted with participants to further illustrate the role of study factors in shaping various dimensions of death anxiety or acceptance and quality of life. In general, results showed that factors assessed in this investigation were significantly correlated with death attitudes and emotional health. When study factors were examined simultaneously, gender, ethnicity, intrinsic religiosity, social support, and future-related regret each were shown to have a unique impact on various aspects of EOL adjustment and distress. The article concludes by offering direction to researchers interested in integrating and extending the empirical study of the attitudes of adults facing serious illness, and underscoring the clinical implications of these findings for professionals offering psychosocial and spiritual care at the end of life.

Adherence in childhood diabetes: results of a confirmatory factor analysis.

In an earlier study (Johnson, Silverstein, Rosenbloom, Carter, & Cunningham, 1986), an exploratory factor analysis identified five components of adherence in childhood diabetes. In this investigation, a simultaneous confirmatory analysis was used to test the equality of this factor pattern across two independent samples. Factors 1 through 4--Exercise, Injection, Diet Type, and Eating/Testing Frequency-were confirmed. Factor 5--Diet Amount--proved to be too complex; the adherence measures comprising this factor (total calories and concentrated sweets consumed) are best treated as separate, single-indicator constructs. The results support a multivariate conceptualization of adherence, offer insight into the nature of the components underlying diabetes adherence, and provide measurement information for reliable component estimation.

The Bumpus house sparrow data: A reanalysis using structural equation models

SummaryWe analysed the data of H.C. Bumpus on the survival of house sparrows (Passer domesticus) using structural equation modelling techniques. Using data on seven morphological variables measured by Bumpus, we tested and confirmed a three-factor model that characterized physical attributes for general size, leg size and head size. Although males were physically larger than females, we found no difference between males and females in the physical attributes as measured by the three factors. Survival increased significantly with increasing general size and was unrelated to leg size and head size. Wing length, independent of its relationship to the general size factor, was also significantly related to survival. Higher survival was found among birds with short wings. Males had a higher survival compared to females. Their higher survival was mediated, to a lesser extent indirectly, through greater size and, to a greater extent directly, through effects of unknown origin. We favour the use of structural equation modelling methods in studies of selection because of their ability to test and confirm or disconfirm hypotheses related to selection events.

Life Regrets and Death Attitudes in College Students

The relationship between death attitudes and life regret was examined in college students. Two types of regret, past-related regret and future-related regret, were defined and measured. The results confirmed the hypothesis, based on a comprehensive model of death anxiety, that both types of regret independently predict fear and avoidance of death. Other background and self variables may affect death anxiety, usually indirectly, by influencing the two types of regret. Death acceptance, on the other hand, was found to be influenced directly by intrinsic religious motivation and indirectly by other background and self variables.

The Structure of Cognitive Speed Measures in Old and Young Adults

The speed hypothesis attempts to explain changes in speed of intellectual functioning with increased age by postulating a central speed mechanism or, in a weaker version, multiple speed mechanisms. In this study the issue of structure of measures of speed was addressed by conducting simultaneous confirmatory factor analyses in two age groups at the level of first order and then at the level of second order factors. Sixteen speed measures were included. The analyses were performed in a sample of 149 elderly adults aged 58 to 73 and in a sample of 147 young adults aged 18 to 33. Five first order factors of speed were found, as hypothesized. A model assuming both invariance of factor loadings and of factor intercorrelations was found to fit well the data. Three second order speed factors were necessary to account for the relationships between the first order speed factors, suggesting that a weak version of the speed hypothesis is correct.

Structural Equation Modeling: Applications

Part I. Theory: 1. Structural equation modelling: an introduction Scott L. Hershberger, George A. Marcoulides and Makeba M. Parramore 2. Concepts of structural equation modelling in biological research Bruce H. Pugesek 3. Modelling a complex conceptual theory of population change in the Shiras moose: history and recasting as a structural equation model Bruce H. Pugesek 4. A short history of structural equation models Adrian Tomer 5. Guidelines for the implementation and publication of structural equation models Adrian Tomer and Bruce H. Pugesek Part II. Applications: 6. Modelling intra-individual variability and change in bio-behavioural developmental processes Patricia H. Hawley and Todd D. Little 7. Examining the relationship between environmental variables and ordination axes using latent variables and structural equation modelling James B. Grace 8. From biological hypotheses to structural equation models: the imperfection of causal translation Bill Shipley 9. Analysing dynamic systems: a comparison of structural equation modelling and system dynamics modelling Peter S. Hovmand 10. Estimating analysis of variance models as structural equation models Michael J. Rovine and Peter C. M. Molenaar 11. Comparing groups using structural equations James B. Grace 12. Modelling means in latent variable models of natural selection Bruce H. Pugesek 13. Modeling manifest variables in longitudinal designs - a two-stage approach Bret E. Fuller, Alexander von Eye Philip K. Wood and Bobby D. Keeland Part III. Computing: 14. A comparison of the SEM software packages Amos, EQS and LISREL Alexander von Eye and Bret E. Fuller Index.This chapter provides an introduction to structural equation modeling (SEM), a statistical technique that allows scientists and researchers to quantify and test scientific theories. As an example, a model from behavioral genetics is examined, in which genetic and environmental influences on a trait are determined. The many procedures and considerations involved in SEM are outlined and described, including defining and specifying a model diagrammatically and algebraically, determining the identification status of the model, estimating the model parameters, assessing the fit of the model to the data, and respecifying the model to achieve a better fit to the data. Since behavioral genetic models typically require family members of differing genetic relatedness, multisample SEM is introduced. All of the steps involved in evaluating the behavioral genetic model are accomplished with the assistance of LISREL, a popular software program used in SEM.

Structure of everyday memory in adults with age-associated memory impairment.

Everyday memory was tested in a group of adults manifesting Age-Associated Memory Impairment; a computerized battery of tests was constructed to simulate memory tasks of daily life. Confirmatory and other structural equation models were estimated for the entire sample of 273 Ss and for 3 age groups. A 4-factor model was found to fit the data well and was invariant across age and gender. After education had been controlled, only the General Recall factor was found to be consistently related to age in both men and women; the other 3 factors--Narrative Memory, Digit Recall, and Visual Memory--were related to age only in men. Confirmatory factor analyses of the everyday memory tests combined with several psychometric memory tests suggested that some of the latter (the Benton Visual Retention Test and Wechsler Memory Scale Hard Paired Associates) load on more than 1 factor of everyday memory, suggesting complex relationships between the 2 types of tests.