Jacob M. Marszalek

Sample Size in Psychological Research over the Past 30 Years

The American Psychological Association (APA) Task Force on Statistical Inference was formed in 1996 in response to a growing body of research demonstrating methodological issues that threatened the credibility of psychological research, and made recommendations to address them. One issue was the small, even dramatically inadequate, size of samples used in studies published by leading journals. The present study assessed the progress made since the Task Forces final report in 1999. Sample sizes reported in four leading APA journals in 1955, 1977, 1995, and 2006 were compared using nonparametric statistics, while data from the last two waves were fit to a hierarchical generalized linear growth model for more in-depth analysis. Overall, results indicate that the recommendations for increasing sample sizes have not been integrated in core psychological research, although results slightly vary by field. This and other implications are discussed in the context of current methodological critique and practice.

Development and Assessment of the Social Issues Advocacy Scale

This article describes the development and the initial psychometric evaluation of the Social Issues Advocacy Scale in two studies. In the first study, an exploratory factor analysis (n = 278) revealed a four-factor scale, accounting for 71.4% of the variance, measuring different aspects of social issue advocacy: Political and Social Advocacy, Confronting Discrimination, Political Awareness, and Social Issue Awareness. The second study (n = 509) supported the structure. Results indicated excellent internal reliability and associations with another social advocacy scale, political interest, and multicultural empathy, but not with self-esteem and life satisfaction; all of which provided initial evidence of construct and discriminant validity.

Longitudinal Multilevel Modeling of Facial Pain, Muscle Tension, and Stress

The role of masticatory muscle activation on pain in temporomandibular muscle and joint disorders (TMJD) is controversial. This single-group, prospective panel study examined the relationships among masticatory muscle tension, emotional distress, and TMJD pain in a sample of 7,023 observations obtained from 171 individuals using longitudinal multilevel modeling. Three main hypotheses were tested. The first posited that emotional distress and muscle tension directly influenced pain (hypothesis 1a: Distress → TMJD Pain; hypothesis 1b: Muscle Tension → TMJD Pain). The second posited that emotional distress directly influenced muscle tension (Distress → Muscle Tension), and the third posited that the effect of emotional distress on pain was mediated by muscle tension (Distress → Muscle Tension → TMJD pain). We also examined the fit of the data to possible alternative models. All the data used in this study were collected via an experience sampling methodology. The fit of the preferred models was better than that of the alternative models, with the preferred models explaining large proportions of the data, especially for level 2 variance (hypothesis 1a = 41% variance; hypothesis 1b = 69% variance; hypothesis 2 = 48% variance). In the mediation model, the addition of muscle tension to the model reduced the impact of emotional distress. The findings support a causal role for masticatory muscle tension in TMJD pain. Clinically, the results suggest that addressing tension and other oral parafunctions in those diagnosed with TMJDs should be an important part of the conservative, noninvasive care of individuals diagnosed with the myofascial pain or arthralgia of TMJD.

Computers and Traditional Teaching Practices: Factors influencing middle level students’ science achievement and attitudes about science

The purpose of this study was to examine the association of middle school student science achievement and attitudes toward science with student-reported frequency of using computers to learn science and other classroom practices. Baseline comparison data were collected on the frequency of student-centred teaching practices (e.g. the use of group experiments during science class) and traditional teaching practices (e.g. having students copy notes during science class) to learn science. The student sample was composed of 294 seventh-grade students enrolled in middle school science. Multiple regression was used to investigate the association of attitudes toward science, student-centred teaching practices, computer usage, and traditional teaching practices with science achievement. Both attitudes toward science and student-centred teaching practices were positively associated with science achievement, and student-centred teaching practice was positively associated with attitude toward science. Computer usage was found to have a negative association with student achievement, which was moderated by traditional teaching practices.

Therapeutic Reactance in a Depressed Client Sample A Comparison of Two Measures

The impact of client variables on psychotherapy is of both theoretical and practical importance. Reactance—the premise that individuals seek to maintain control over personal freedoms when threatened by a perceived loss thereof—has been shown to have an impact on the effectiveness of therapeutic interventions. Developing an effective means of quantitatively assessing this characteristic prior to treatment could facilitate treatment planning and maximize treatment outcome. The present study compared two paper-and-pencil measures of reactance: the Therapeutic Reactance Scale (TRS) and Resistance Potential (RP). Ninety-eight men and women diagnosed with depression completed both measures. The TRS and RP failed to correlate despite their presumed ability to measure the same construct. The RP exhibited extremely poor internal consistency, calling into question results that have been based on this measure. The TRS results provided evidence of convergent, divergent, and construct validity for this instrument.

An Empirical Investigation of Viktor Frankl’s Logotherapeutic Model

The purpose of this study was to investigate the logotherapeutic model as described by Frankl that explains the relationships among the search for meaning in life, the presence of meaning in life, existential vacuum, existential frustration, noogenic neurosis, will-to-power, and will-to-pleasure. A sample of college students from a large Mid-Atlantic university (N = 750) completed paper-and-pencil instruments for the variables. Structural equation modeling was used to test and compare four competing alternative models of the relationships among the aforementioned constructs. Two models exhibited excellent fit, one model good fit, and the fourth model poor fit. Of the two best models, one treated will-to-power and will-to-pleasure as outcomes of noogenic neurosis and the other treated them as causes of noogenic neurosis. Limitations, suggestions for future research, and implications for clinical practice are also discussed.

Statistical analysis of low molecular mass heparin Nanoencapsulation

Statistical analysis of low molecular mass heparin Nanoencapsulation The objective of this study was to use Box-Behnken design (BBD) to investigate the influence of formulation variables on the properties of heparin-loaded poly(lactic-coglycolic acid) (PLGA)-polymethacrylate-RLPO (E-RLPO) nanoparticles (NP) in terms of mean diameter (as size) and drug encapsulation efficiency. The NPs were prepared by the double emulsion solvent evaporation method. The independent variables were: X1 - polymer mass ratio (PLGA:E-RLPO) in the oil phase, X2 - concentration of polyvinyl alcohol (PVA) as emulsion stabilizer, and X3 - volume of the external aqueous phase (W2). Particle size (analyzed by dynamic light scattering) and encapsulation efficiency (EE, estimated by spectrophotometry) were the investigated responses. The polynomial equation obtained from regression analysis of the reduced model (p = 0.0002, F = 25.7952 and R2 = 0.96) provided an excellent fit. The optimal size for the NP was found to be 134.2 ± 16.5 nm with formulation variables of 48.2:61.8, 0.321 (%,m/V) and 263 mL for X1, X2 and X3, respectively. Probably, due to electrostatic interaction between the negatively charged drug and the positively charged E-RLPO, the percent EE of heparin was between 74.4 ± 6.5 % (lowest value) and 92.1 ± 5.3 % (highest value). The data suggest that BBD is a useful tool in rational design of heparin-loaded NPs. Statistička analiza nanokapsuliranja niskomolekularnog heparina Box-Behnkenovo dizajniranje (BBD) primijenjeno je za praćenje utjecaja formulacijskih varijabli na svojstva nanočestica (NP) s heparinom. Za izradu nanočestica korišten je kopolimer mliječne i glikolne kiseline (PLGA) i polimetakrilat-RLPO (E-RLPO). Nanočestice su pripravljene metodom dvostruke evaporacije otapala iz emulzije. Nezavisne varijable bile su: X1 - omjer masa polimera (PLGA : E-RLPO) u uljnoj fazi, X2 - koncentracija polivinil alkohola (PVA) kao stabilizatora emulzije i X3 - volumen vanjske vodene faze (W2). Zavisne varijable bile su veličina čestica (analizirana pomoću dinamičkog rasapa svjetlosti) i učinkovitost inkapsuliranja (EE) (praćena spektrofotometrijski). Polinomska jednadžba dobivena regresijskom analizom reduciranog modela odlično je odgovarala (p = 0,0002, F = 25,7952 i R2 = 0,96). Optimalna veličina nanočestica bila je 134,2 ± 16,5 nm s formulacijskim varijablama 48,2:61,8, 0,321 (%, m/V) i 263 mL for X1, X2 odnosno X3. Vjerojatno je zbog elektrostatskih interakcija između negativno nabijene ljekovite tvari i pozitivno nabijenog E-RLPO učinkovitost inkapsuliranja heparina varirala od 74,4 ± 6,5 % (najniža vrijednost) do 92,1 ± 5,3 % (najviša vrijednost). Rezultati sugeriraju da je BBD vrlo korisno u racionalnom dizajniranju nanočestica s heparinom.

Comparison of factor structure models for the Beck Anxiety Inventory among cardiac rehabilitation patients

OBJECTIVE Individuals with cardiovascular disease (CVD) experience greater rates of distress symptoms, such as anxiety and depressive symptoms, than the general population. These psychological outcomes have been linked to greater risk for negative outcomes following a cardiac event; however, research examining the relationship between specific components of anxiety and outcomes in CVD is limited. Further, prior research has not investigated the structure of anxiety symptoms in CVD. This study sought to compare previously established one, two, and four-factor models of the Beck Anxiety Inventory (BAI) in individuals enrolled in cardiac rehabilitation (CR). METHODS Our sample included 208 individuals with CVD recruited during enrollment in a phase II CR program. Participants completed the BAI at enrollment in CR (Time 1) and again 12weeks later at CR completion (Time 2, n=151). RESULTS Consistent with prior literature, 41% of our sample reported at least mild symptoms of anxiety (BAI>8), and the BAI proved to be a reliable measure within this sample (α=0.89). Confirmatory factor analysis (CFA) results indicated that a second-order model with four first order factors, consisting of cognitive, autonomic, neuromotor, and panic components, fit our data well. A multi-group CFA approach supported measurement invariance across time. CONCLUSION These results suggest that anxiety following CVD can be evaluated based on cognitive, autonomic, neuromotor, and panic components as well as the encompassing anxiety construct.

Validation of a TAI Short Form with an Adolescent Sample

ABSTRACT Although test anxiety is increasingly used in research with multiple constructs, it is not always possible to administer a lengthy scale to measure it. Taylor and Deane (2002) developed a 5-item short form of the 20-item Test Anxiety Inventory (TAI; see Spielberger, Gonzalez, Taylor, Algaze, & Anton, 1978). Although evidence of reliability and validity was good, there were several limitations, including the age and gender of the sample, and the lack of data obtained with the short form rather than the original TAI. The current study attempts to address those limitations and augment previous results with additional types of validity evidence (i.e., coefficients of divergent validity and exploratory factor analysis) in a sample of 152 seventh- and eighth-graders. Results were high reliability (.86) and good evidence of multiple facets of validity. Previous results were confirmed and extended for adolescents and for use in applied psychological and educational settings.

Social justice advocacy among doctoral students in professional psychology programs

This study examined the relationships among multicultural competency, task-oriented coping, spirituality, political involvement, and experiences of discrimination on students’ engagement in social justice advocacy in a sample of 412 clinical, counseling, and school psychology doctoral students. Specifically, this study examined the mediating role of political involvement and task-oriented coping between the predictor variables and social justice advocacy. The results showed that the relationship between experiencing discrimination and social justice advocacy was only present when participants reported more political involvement and more task-oriented coping. The same was true for the relationship between spirituality and social justice advocacy; this relationship was only present when going through task-oriented coping. Further while there was a relationship between students’ multicultural knowledge and social justice advocacy, it was partly accounted for by political involvement. Similarly, the relationship between multicultural awareness and social justice advocacy was partly accounted for by task-oriented coping. Implications and recommendations for future research are addressed.