Exploratory factor analysis of PROMIS-29 V1.0, PROMIS Global Health and the RAND SF-36 from chiropractic responders attending care in a practice-based research network

Background The SF-36 questionnaire is perhaps the most widely used quality of life instrument in the world today, while the PROMIS instruments continue to gain popularity. Given their continued use in chiropractic research and practice, we examined their latent domain structure using exploratory factor analysis (EFA). Methods To uncover latent structures of a large series of measured variables from the PROMIS-29, PROMIS Global Health and RAND SF-36 domains, we defined a factor analysis model represented by the equation $$X = \mu + \Lambda F +\epsilon$$ X = μ + Λ F + ϵ , where $$X = (X_{1} , \ldots ,X_{p} )^{T}$$ X = ( X 1 , … , X p ) T is the matrix of random vectors corresponding to the domains with a mean of $$\mu$$ μ and the covariance matrix $$\Sigma ,$$ Σ , $$\Lambda = \{ l_{jk} \}_{pxm}$$ Λ = { l jk } pxm denotes the matrix of factor loadings, $$F = (F_{1} , \ldots ,F_{m} )^{T}$$ F = ( F 1 , … , F m ) T denotes the matrix of unobserved latent variables that influence the collection of domains and $$\epsilon = (_{1} , \ldots ,_{p} )^{T}$$ ϵ = ( 1 , … , p ) T is the vector of latent error terms. The matrix of item responses X was the only observed quantity with restrictions such that variable scores were uncorrelated and of unit variance with the latent errors being independent with the variance vector $$\psi$$ ψ . The inherited structure of X was expressed simply by $$\Sigma = \Lambda \Lambda^{T} + \psi$$ Σ = Λ Λ T + ψ . Orthogonal and oblique rotations were performed on the $$\Lambda$$ Λ matrix with this equation to improve clarity of the latent structure. Model parameters $$\left( {\mu ,\Lambda ,\psi } \right)$$ μ , Λ , ψ were optimized using the method of minimum residuals. Each EFA model was constructed with Pearson and Polychoric correlation. Results For the PROMIS-29, domains were confirmed to be strongly correlated with Factor 1 (i.e., mental health) or Factor 2 (i.e., physical health). Satisfaction with participation in social roles was highly correlated with a 3rd factor (i.e., social health). For the PROMIS Global Health Scale, a 2-factor EFA confirmed the GPH and GMH domains. For the RAND SF-36, an apparent lack of definable structure was observed except for physical function which had a high correlational relationship with Factor 2. The remaining domains lacked correlation with any factors. Conclusion Distinct separation in the latent factors between presumed physical, mental and social health domains were found with the PROMIS instruments but relatively indistinguishable domains in the RAND SF-36. We encourage continued efforts in this area of research to improving patient reported outcomes.

A Psychometric Re-Examination of the Science Teaching Efficacy and Beliefs Instrument (STEBI) in a Canadian Context

A teacher’s self-efficacy has been found to be one of the most important factors contributing to a successful teaching–learning outcome for both the teacher and the students. Numerous studies have shown that there is a relationship between students’ self-efficacy, students’ academic achievement, teacher burnout and a teacher’s sense of self-efficacy. In this study, the psychometric properties of the Science Teaching Efficacy and Beliefs Instrument (STEBI) by Riggs and Enochs (1990) were re-examined in a Canadian context utilizing data of 1630 teachers from the Pan-Canadian Assessment Program (PCAP) in 2013. Exploratory factor analysis (EFA) and its associated methods were used to investigate the factorial structure of the STEBI, and Cronbach’s alpha was calculated as a measure of reliability. The results showed adequacy of a two-factor solution and similar overall patterns of factor loadings across orthogonal and oblique rotations. In terms of reliability analysis, both factors had reliability coefficients lower than the original scale. The implications of these findings and the future directions for research are discussed.

Satisfaction with family planning services - interpersonal and organisational dimensions

In South Africa, client satisfaction with the quality of health care has received minimal attention; probably due to the lack of locally developed and tested measures. Therefore, we developed and tested a 20-item attitude scale to determine satisfaction with Family Planning (FP) services. The objectives of this study were to: ascertain reliability of the scale and confirm, through factor analysis, that satisfaction with the FP service was based on interpersonal and organisational dimensions. The sample comprised 199 black adult interviewees (158 women and 41 men), who had previously used or were currently using contraception, from an informal settlement in Gauteng, South Africa. Three items were removed from the scale due to unacceptable communality estimates. The reliability coefficient of 0.76 for the 17-item scale was satisfactory. The principal components analysis, with orthogonal and oblique rotations, extracted two factors; accounting for 51.8% of the variance. The highest loadings on Factor I involved an interpersonal dimension (friendly, encouraging, competent, informative and communicative). Factor II tended to focus on the organisational elements of the system, such as different methods, choice of methods, service availability and length of waiting time. It was concluded that this scale was a reliable, easily administered and scored measure of satisfaction, with underlying interpersonal and organisational dimensions.

The Health Professions Stress Inventory: Factor Structures for Pharmacists

Scores from a sample of pharmacists on the Health Professions Stress Inventory were factor analyzed to identify any underlying components of these professionals' job-related stress. Data were collected via mail questionnaires from a nationwide sample of 573 practicing pharmacists. Three- and four-factor solutions, using both orthogonal and oblique rotations, were compared. Based on these comparisons, a four-factor oblique solution was judged to be most appropriate, the four factors being labeled Professional Recognition, Patient Care Responsibilities, Job Conflicts, and Professional Uncertainty. The factors show evidence of internal consistency and construct validity.

Changes in the Ecological Structure of Hong Kong 1961–1971: A Comparative Analysis

Two sets of data from the 1961 and 1971 censuses of the colonial city of Hong Kong have been factor analysed by various methods that have been subjected to orthogonal and varimax rotations. Interpretations have revealed two robust factors of ‘high-income expatriate workers’ and ‘low-income blue- and white-collar workers’ in 1961. By 1971 a more diversified socioeconomic stratification of the Chinese and high-income expatriate workers had emerged. A new ‘public-housing residents’ dimension also appeared. The spatial patterns of the social areas of Hong Kong over a decade, obtained by a numerical procedure of cluster analysis, have also been compared, and the massive involuntary redistribution of population that resulted in the creation of a peripheral, government public-housing area in the previously rural—urban fringe area has been noted. These lead to some theoretical considerations of the validity of Western urban theories and concepts since the Hong Kong spatial pattern tends towards a greater degree of regularity. It is also recommended that the orthogonal and oblique rotations can complement each other to give the macro and micro variations of the urban dimensions.

Dimensionality of the Rotter Interpersonal Trust Scale

The Rotter Interpersonal Trust Scale was interspersed in a larger questionnaire completed by 187 paid undergraduates. Its dimensionality was investigated through cluster analysis and orthogonal and oblique rotations following a principal axis factor solution. Four dimensions, designated “Political Cynicism,” “Interpersonal Exploitation,” “Societal Hypocrisy,” and “Reliable Role-performance” were identifiable across techniques. This finding of multi-dimensionality underscores the incongruence between Rotter's definition and his measure of interpersonal trust. Studies supporting the multidimensional interpretation are discussed. Scoring these four dimensions in addition to the total scale is recommended. A short form of the scale consisting of the three marker items for each dimension is proposed. This short form is efficient, and it retains the dimensionality of the total scale.

MULTIVARIATE ANALYSIS OF GENETIC VARIATION

ABSTRACT Multiple factor analysis was used to interpret geographical variation of gene frequencies. Allelic frequencies at three loci (two esterase loci, Esr and Esh, and a malic dehydrogenase locus) from ants (Pogonomyrmex barbatus) collected throughout Texas and reported by Johnson et al. (1969) were reexamined for patterns of correlation with five environmental measurements: mean January temperature, mean July temperature, mean annual precipitation, elevation, and annual growing season. These measurements and the associated gene frequencies at each sampling location were subjected to factor analysis. Variables highly correlated with the same factor were hypothesized to be causally related. Both orthogonal and oblique rotations of the factor solution provided four factors with essentially the same interpretation. Variation at the Esh locus was associated with a continuum from cold-wet to hot-dry. Variation at the Mdh locus and some of that at the Esr locus was related to the severity of winter months. Other allelic frequencies at the Esr locus had high correlations with a third factor which seemed to be independent of the environmental measurements. None of the allelic frequencies had high correlations with the fourth factor which was interpretable as an altitudinal gradient.

A Factor-Analytic Study of the Articulation of Selected English Consonants

This study obtained the results of a factor analysis of speech articulation data for a sample of elementary school children with functional articulation disorders. A principal components type factor analysis yielded 11 factorially distinct components which could be interpreted in terms of the common placement classification of Fairbanks (1960). Seven of the pretest-posttest reliabilities and five of the split-sample reliabilities for the 11 factors exceeded 0.80. There was little difference between components derived from orthogonal and oblique rotations. The findings of this study and of Schutz, Mowrer, and Baker (1964) raise important questions regarding the validity of the concept of phonetic context in articulation testing for classes of phonemes other than the stops. Moreover, the identification of 11 articulation component scores suggests that articulation research using the multivariable approach proposed would provide more accurate, detailed information concerning a student’s articulation proficiency, as well as information regarding relationships among articulation variables which are obscured when a single measure is used.