Exploratory Factor Analysis Procedures Research Articles

Students' Self-Regulated Learning in Physics: Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA)

This study aims to develop and validate an instrument that measures students' self-regulated learning in Physics. The pilot study involved 400 randomly selected Form 4 students taking Physics. Exploratory Factor Analysis (EFA) was conducted to assess the suitability of the measurement items and to identify the construct dimensions. Three main components were identified through the EFA procedure, namely self-motivation (DP), metacognitive planning (PM), and metacognitive monitoring (PK). The field study involved 435 Form 4 students taking Physics from daily secondary schools. The study population consisted of Form 4 students from daily secondary schools across Peninsular Malaysia. The sample was selected using stratified random sampling and simple random sampling from four states: Perak, Kedah, Negeri Sembilan, and Kelantan. Data from the field study were used to confirm the validity and reliability of the instrument through the Confirmatory Factor Analysis (CFA) procedure. CFA results indicated that the developed instrument is valid and reliable for measuring students' self-regulated learning. Once the measurement model was confirmed through CFA, the researchers structured these constructs into a structural model and estimated the necessary parameters using the Structural Equation Modelling (SEM) procedure. This study makes a significant contribution by producing a valid and reliable instrument for measuring self-regulated learning among Form 4 Physics students. This instrument can be used in future research to enhance the understanding of factors influencing students' self-regulated learning in the context of Physics education.

Measuring Satisfaction with Life-construct among University Students during Covid-19 Pandemic in Sabah, Malaysia

This research intended to develop a valid and reliable instrument of the Satisfaction with Life Scale (SWLS) to measure satisfaction with life (SWL) constructs among 108 university students in Sabah, Malaysia, through the exploratory factor analysis (EFA) procedure. Using the extraction method of Principal Component Analysis (PCA) with Varimax Rotation, a component of the SWL construct is extracted with an eigenvalue of 3.1. The variance explained for this component is 62%. The construct of SWL has Cronbach's alpha value of .817. The development scale and validation confirmed that the instrument is consistent and stable with university student samples.

Examining the mediating and moderating roles of social marketing behavioural enhancers regarding consistent condom use.

Since their importance was highlighted by Ayikwa and De Jager, social marketing behavioural enhancers (SMBEs) have been investigated in terms of their causal and correlational relationships with the intention to use condoms (IUC) and consistent condom use (CCU), as people often fail to act on their intentions. However, scrutiny of their mediating and moderating roles could provide insights pertinent to the design of effective HIV and AIDS preventative programmes. This study examined whether perceived behavioural control (PBC) and IUC interact with exposure to HIV and AIDS information (EI), ease of access to condoms (EAC) and level of related knowledge (KN) in determining CCU. It also investigated whether PBC and IUC predict CCU through increasing EI, EAC, and KN. A quantitative approach was adopted and data were collected from 607 participants, aged at least 18, living in Gauteng Province, South Africa. The questionnaire administered included pre-existing items, validated through exploratory and confirmatory factor analysis procedures. Regression analyses of the data for mediation and moderation testing were performed using PROCESS macro software for SPSS. The results indicated that none of the SMBEs mediated the non-significant PBC-CCU relationship: B = -0.0258, SE = 0.0199, p = 0.195. Nor did they mediate the significant IUC-CCU relationship: B = 0.0395, SE = 0.0195, p = 0.043. Similarly, none of the SMBEs were found to moderate the PBC-CCU relationship (EI*PBC: B = 0.0034, SE = 0.0056, p = 0.540; KN*PBC: B = -0.0006, SE = 0.0064, p = 0.931; EAC*PBC: B = 0.0011, SE = 0.0059, p = 0.854) as IUC-CCU relationship (EI*IUC: B = 0.0036, SE = 0.0054, p = 0.513; KN*IUC: B = -0.0096, SE = 0.0060, p = 0.111; EAC*IUC: B = 0.0044, SE = 0.0061, p = 0.469). A recommendation is made to scrutinise the mediating and moderating roles of SMBEs in the context of health behavioural models other than the theory of planned behaviour, which was considered in this study.

Incivility, Mobbing, and Abusive Supervision: A Tripartite Scale Development Study

Using qualitative and quantitative methodologies, in three consecutive studies with employed samples, we developed measures of workplace incivility, mobbing, and abusive supervision sensitive to the nuances of a non-Western context (i.e., Türkiye). In Study 1, we first conducted 15 focus groups (N = 149), identified culture-specific and universal themes underlying the focal mistreatment types, and developed the initial scales. We then pilot-tested (N = 427) and refined the scales using exploratory factor analytic procedures. In Study 2, confirmatory factor analyses (N range = 456-524) and associations between the new scales and their widely used counterparts (N = 353) yielded evidence for the construct validity of the scales. Study 2 also involved the development of short forms of relatively long incivility and abusive supervision scales. In Study 3 (N = 482), we first examined the extent to which the three scales were operationally distinct. Second, we examined the scales’ ability to predict burnout and organizational commitment. Results supported operational distinctiveness as well as the criterion-related validity of the scales. A dominance analysis revealed that the three scales had equivalent contributions in explaining the two outcome variables, further justifying their distinctiveness. We argue that the use of present scales is not necessarily restricted to the Turkish context and may prove useful more broadly in other neo-traditional contexts.

Exploring Digital Technology Usage among English Language Instructors at a Saudi Higher Education Institution and Validating a Hierarchical Structure of Usage Based on the SAMR Model

This study examined the usage of digital technology among English language instructors at a public university in Saudi Arabia as perceived by their students and tested the notion that such usage could be ranked in hierarchical levels. The SAMR model, developed by Puentedura (2014), was employed to categorise and rank technology usage into four incremental levels, i.e., Substitution, Augmentation, Modification and Redefinition, with Substitution being the most rudimentary level and Redefinition being the highest and most sophisticated usage. A 32-item questionnaire rated on a 5-point Likert scale measuring how frequently English language instructors used technology at the four SAMR levels was developed by the authors, content-validated by six instructional technology experts and pilot-tested with 63 students prior to its use in the actual survey. Data were gathered from a survey sample of 535 Saudi learners studying English in their foundation year programme and analysed using three statistical procedures, i.e., descriptive statistics, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The descriptive results pointed to instructors' technology usage revolving around the Substitution level of the SAMR model, indicating a predominant tendency among instructors to merely replace traditional teaching tools with digital alternatives. The EFA procedure (via Principal Axis Factoring with Promax rotation) produced conflicting results. While the extracted factor structure supported only two levels of usage, the scree plot suggested the existence of four usage levels consistent with the SAMR model. This was addressed by the subsequent CFA procedure performed on the data that confirmed the four SAMR levels, with the fit statistics indicating a good-fitting technology usage model; χ2(98) = 268.73; χ2/df = 2.74; CFI = .94; RMSEA = .078, CI: .067, .090. Sixteen out of the 32 technology usage items were successfully extracted and confirmed as the indicators SAMR’s four levels. The results corroborated previous findings that technology utilisation among English instructors is pervasive but rudimentary. They also supported the theoretical notion that technology usage can be categorised, ranked, and understood in hierarchical levels as purported by the SAMR model.

Exploring Items for Measuring the Sales and Service Tax (SST) Compliance Constructs using Exploratory Factor Analysis (EFA) Procedure

Exploring Items for Measuring the Sales and Service Tax (SST) Compliance Constructs using Exploratory Factor Analysis (EFA) Procedure

Teachers' digital competences: a scale construction and validation study.

Improving teachers' digital competences is sine qua non for effective teaching and learning in today's digital society. However, there is a limited number of comprehensive and reliable scales to measure teachers' digital competences. Regarding this, the present study aimed to develop and validate a comprehensive scale to assess teachers' digital competences. Building on previous studies, a draft scale developed and piloted with a sample of teachers from all educational levels. The procedures of Exploratory Factor Analysis (EFA) were followed to refine the scale, resulting in a five-point Likert scale with 36 items loaded onto four factors. The final scale was called as Teachers' Digital Competences Scale (TDC-S). Confirmatory factor analysis (CFA) was employed to validate the four-factor structure. Reliability analysis was performed using Cronbach's alpha (α), McDonald's omega (ω), and Composite Reliability (CR), indicating high psychometric properties. Convergent and discriminant validity analyses were also performed to assess the validity of the latent structures in TDC-S. The findings suggest that the TDC-S is a valid and reliable instrument for assessing teachers' digital competences at all grade levels from primary to high schools. It can be used to inform teacher training and development programs, and to identify teacher candidates who need additional assistance regarding improving their digital competences.

55 Psychometric Properties of the Verbal Series Attention Test: Preliminary Findings

Objective:To investigate the latent factor structure and construct validity of the Verbal Series Attention Test (VSAT) across clinical patient populations.Participants and Methods:Participants included a consecutive series of clinical patients presenting with a primary memory complaint. Each patient underwent a comprehensive neuropsychological assessment and provided informed consent to allow their clinical data to be used for research. Groups formed included 1) No Neurocognitive Disorder [NoND, N=262, mean age=68.8, mean education=16.2, mean MMSE=28.3], 2) Mild Neurocognitive Disorder [MildND, N=337, mean age=72.3, mean education=15.4, mean MMSE=28.7], and 3)Major Neurocognitive Disorder [MajorND, N=524, mean age=76.5, mean education=14.5, mean MMSE=19.0] with etiologies including suspected Alzheimer’s disease and/or vascular pathology. Latent factors were investigated using exploratory factor analysis (EFA).Results:EFA was conducted using SAS 9.4 software and the promax (oblique) rotation to reveal the latent factors of the eight timed items of the VSAT in each of the three clinical groups. The structure was essentially identical in all three groups with two primary factors consistently emerging identified as 1-Complex Attention and 2-Simple Attention. Each factor had four items loading with a correlation range of > 0.37 x < 0.92. The internal consistency (Cronbach’s alpha) for the VSAT total score in each group was excellent (NoND a=0.83, MildND a=0.81, and MajorND a=0.84). To investigate construct validity, the VSAT items were entered into factor analysis with measures of attention and executive function (i.e., Digit Span [forward, backward, sequence], Trail Making Test A & B, semantic fluency (animals), Controlled Oral Word Association Test [COWAT, FAS]). All three patient groups were combined (N=950) given the VSAT’s consistent factor structure. Using the same EFA procedure as before, two main factors emerged with the VSAT Complex Attention variables loading on a general complex attention/working memory factor including Trails B, semantic fluency, and Digit Span subtests. The VSAT Simple Attention items loaded on a general attention factor with the VSAT Simple Attention variables and Trails A. COWAT did not load significantly on either factor.Conclusions:The latent factor structure of the VSAT was consistent across patient populations with excellent internal consistency in each clinical group. The Complex and Simple Attention factors of the VSAT loaded on factors with similar variables identifying the anticipated latent factor structure demonstrating the construct validity of the VSAT across a wide spectrum of cognitive impairment in patients with primary memory complaints ranging from NoND to MajorND. This supports the use of the VSAT in patients across neurocognitive severity. Future studies will further explore additional psychometric properties of this instrument.

Evaluation of Psychometric Characteristics of A Logical Reasoning Tool With The Classic Test Theory Approach

Research on logical reasoning began to be carried out in Indonesia, it is necessary to conduct an evaluation of the psychometric characteristics possessed by logical reasoning measurement tools made by researchers. Logical reasoning measurement tools made by researchers need to be re-evaluated considering there are weaknesses in terms of using a relatively small number of subjects, so that it can affect the standardization of logical reasoning measuring devices. This study aims to obtain an overview of item difficulty index, item discrimination index, effectiveness of the distractors, validity, reliability, and error measurement from the logical reasoning measurement tool. Respondents in this study amounted to 7.730 students, consisting of 3.897 men and 3.833 women with an age range of 15-19 years. The research data were analyzed with the help of Microsoft Excel 2007, SPSS version 22.00, and ITEMAN version 3.6. The results of this study indicate that the item difficulty index moves from 0.35 to 0.80 which belongs to the easy and medium category. This study also shows that the item discrimination index moves from 0.10 to 0.71 with four items rejected and need to be aborted. This study also shows that the effectiveness of the distractors contained in each item in the logical reasoning measure is in the effective category. This study also shows that each item in the logical reasoning measure is considered valid in terms of factorial validity through exploratory factor analysis (EFA) procedures. This study also shows that the measurement of logical reasoning is relatively reliable with a Cronbach Alpha coefficient of 0.906. This study also shows that the measurement error obtained in this study is ± 3.92 of the total score obtained using a logical reasoning measure with a confidence level of 95%, with the actual score estimate obtained by respondents moving from 12.08 to 19.92, if the scores obtained by respondents sixteen.

Satisfaction with life among public and private university students in Sabah, Malaysia: A modification scale using factor analysis

This research intended to develop a valid and reliable instrument of the Satisfaction with Life Scale (SWLS) to measure satisfaction with life (SWL) constructs among public and private university students in Sabah, Malaysia, through the exploratory factor analysis (EFA) procedure. The pilot study obtained a sample of 108 students from public and private education institutions in Sabah, Malaysia, through an online survey using a self-administered questionnaire. The researchers performed the EFA procedure on SWL construct using IBM SPSS 25. The Bartletts' Test of Sphericity is highly significant (Sig. = .000). Furthermore, the sampling adequacy by Kaiser‒Meyer‒Olkin (KMO = 0.839) is excellent. Using the extraction method of Principal Component Analysis (PCA) with Varimax Rotation, a component of the SWL construct is extracted with an eigenvalue of 3.101. The variance explained for this component is 62.030%. The construct of SWL has Cronbach's alpha value of .817. The development scale and validation confirmed that the instrument is consistent and stable with both private and public college and university student samples. It adds a remarkable contribution to the measurement of SWLS, mainly in the context of higher education institution students. The EFA outcomes formed a configuration that extracts a component of SWL, which can be measured by the original five items established in this research. This research reveals that the SWL construct is applicable in this study.

Measuring Physical Education Teacher Socialization With Respect to Comprehensive School Physical Activity Programming

Purpose: Utilizing teacher socialization in physical education theory, the aim of this study was to develop a survey to measure physical education teachers’ socialization experiences and comprehensive school physical activity program involvement. Method: Instrument development included a review of existing comprehensive school physical activity program and socialization instruments, Delphi method to evaluate face and content validity through expert feedback, and a pilot test to examine the instrument’s psychometric properties. Results: Upon completion of expert feedback, three items were removed, four items were revised, and open-ended questions were added to each survey construct. The pilot test yielded 28 completed surveys (40% response rate). Bayesian exploratory factor analytic procedures showed that items had statistically significant loadings and were quality measures of the corresponding constructs. Survey subscales had acceptable and high internal consistency coefficients. Discussion/Conclusion: Results suggest that this instrument is a trustworthy tool for continued research examining physical education teachers’ socialization and comprehensive school physical activity program involvement.

Evaluating Psychometric Properties of the International Knee Documentation Committee Subjective Knee Form in a Heterogeneous Sample of Post-Operative Patients.

The International Knee Document Committee Subjective Knee Form (IKDC-SKF) is a patient-reported outcome measure used in orthopedics and sports medicine. Further psychometric assessment is necessary to confirm measurement properties in a large, heterogenous sample. The purpose of the study was to assess the psychometric properties of the IKDC-SKF in a large, heterogenous sample. Cross-Sectional Study. An exploratory factor analysis (EFA) was conducted to identify a sound latent structure and to assess internal consistency in a large sample of patients who underwent knee arthroscopy. A confirmatory factor analysis (CFA) was conducted to confirm structural validity. Multi-group invariance was conducted to assess factorial stability across sex and age groups, while longitudinal invariance procedures were performed to assess stability over time. A 3-factor, 9-item IKDC-SKF short form was identified with EFA procedures. The model was confirmed with CFA (CFI = 0.983; TLI = 0.975; IFI = 0.983; RMSEA = 0.057), while a sound 2-factor, 6-item model was also identified (CFI = 1.0; TLI = 0.999; IFI = 1.0; RMSEA = 0.11). The 9-item IKDC-SKF short form was invariant across groups but not time; removal of a single item (i.e., 8-item IKDC-SKF short form) resulted in longitudinal invariance. The 6-item IKDC-SKF short form was invariant across groups and time. The 6-item, 8-item, and 9-item short form versions of the IKDC-SKF exceed contemporary fit recommendations and present as plausible alternatives to the IKDC-SKF with improved measurement properties, reduced scale response burden, and evidence of multi-group and longitudinal invariance. Further, the 6- and 8-item IKDC-SKF short forms may be used to assess group differences or change across time.# Level of evidence hereLevel 3©The Author(s).

Exploratory Factor Analysis for Technostress Among Primary School Teachers

The aim of this study was to explore and develop instruments for measuring technostress among primary school teachers in Malaysia. The researchers adapted 28 items from previous study and modified the statement to suit current study. Then the items statement was translated into Malay language to suit the local setting. The instruments underwent expert verification for content validity, face validity and criterion validity. The study amended the item statement accordingly based experts’ comment. For pilot study, some 106 school-teachers were selected randomly for data collection. The data were explored and validated through exploratory factor analysis (EFA) procedure. The results of the EFA procedure revealed the 28 items fall into five underlying components. The components are renamed as technical oriented, profession oriented, social oriented, personal oriented and teaching-learning process oriented. The items under these five components explained 71.1% of the total variance. The internal reliability of the technostress construct was 0.95. In addition to adding to the current body of knowledge, the findings provide a reliable source of information for researchers and professional practitioners interested in future research in technostress for educators, particularly primary school teachers.

Exploratory Factor Analysis: Validity and Reliability of Teacher's Knowledge Construct Instrument

The study aims to determine the instrument's validity and reliability in measuring the construct of teachers' knowledge. The cross-sectional survey research design used a quantitative approach, with pilot study data obtained from 100 primary school teachers of the Trust School Programmed in Selangor, Malaysia. The selection of the samples was based on a two-stage random sampling strategy. In this study, the teacher's knowledge instrument was used to measure teachers’ knowledge in implementing a cooperative learning structure. The Exploratory Factor Analysis (EFA) procedure was employed to identify the factor loading value of each item, as well as the number of components for the teacher's knowledge construct. The EFA results demonstrate three components for the construct of teacher knowledge with the eigenvalue of each component exceeding 1.0, i.e., content knowledge, pedagogical knowledge and technological knowledge. The reliability of the content knowledge component was 0.966, of the pedagogical knowledge component was 0.967 and of the technological knowledge component was 0.961. The total construct of the teacher's knowledge was 0.967. The entire construct of teachers’ knowledge achieved the requirements for the validity and reliability of the construct. The study’s instruments can be used by other researchers to measure the construct of teachers' knowledge in other contexts.

Tıp Fakültesi Öğrencilerinin İngilizce Öğrenme Motivasyonları Ölçeğinin Geliştirilmesi

This study aims to develop a scale determining the extrinsic, integrative, and intrinsic factors that motivate medical students learning English as a foreign language in an ESP context. Derived from Gardner and Lambert’s socio-educational model (1972) and Deci and Ryan’s self-determination theory (1985), the study is based on the motivational framework of Noels et al. (2000) which categorizes the three main motives as intrinsic, instrumental and integrative. With the participation of 320 medical students, a 14-item scale was developed with satisfactory internal consistency. Four different methods were used to create the motivation scale. First, a focus group interview was conducted with the participation of randomly selected medical students, and 22 items were determined as a result of the content analysis and were sent to five medical doctors for their opinions, and 6 items were removed from the pool upon their feedback. Next, the literature was reviewed and comparisons were made between existing scales. Finally, based on the opinions of 3 English for Specific Purposes (ESP) experts from the field, the concept of extrinsic motivation was used instead of instrumental motivation, and a 16-item five-point Likert type scale was decided. Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) statistical procedures were also utilized. Principal Components Factor Analysis (PCA) was applied to reveal the construct validity of the motivation scale, and Direct Oblimin with Kaiser Normalization method was applied as the rotation method. In order to calculate the adequacy of the sample, the Kaiser-Mayer-Olkin (KMO) coefficient was calculated. Finally, as a result of Bartlett sphericity tests to detect correlations between the items, it was determined that the norm values were provided for all statistical processes for the 3-factor structure explaining 64.62% of the total variance. Finally, this study presents a new data collection tool that is statistically valid and reliable to measure medical students’ motivational factors.

Studentsʼ Willingness to Communicate in English: Czech Adaptation of Willingness to Communicate Inside the Classroom Scale

Quality communication between a teacher and a student or students contributes to the process of learning a foreign language. Communication in foreign language teaching is both a means of communication and the content of teaching. The model of willingness to communicate in a foreign language describes individual characteristics and situational variables that affect a pupil’s readiness to enter dialogue with another person at some point. The present study provides information on the process and results of scale adaptation Willingness to Communicate Inside the Classroom scale. The process of adaptation to Czech conditions includes the verification of content validity, construct validity, and the identification of a factor structure of the instrument. Using exploratory factor analysis (EFA) procedures in the JASP program 0.14.1. the suitability of the use of the originally designed scale was verified and a reduction from twenty-seven to eighteen items was proposed. The internal consistency of the Czech version of the Willingness to Communicate Inside the Classroom scale showed a sufficient Cronbach’s alpha coefficient of .82, thus we can assume that the tested scales show sufficient reliability.

Introducing the Home Learning Environment Questionnaire and examining the profiles of home learning environments in Greece

The Home Learning Environment (HLE) plays a prominent role in children’s development. Several measures have been developed to assess its quality; however, most of them seem to mainly focus on specific aspects of the HLE construct. The aim of this study was to develop and validate the Home Learning Environment Questionnaire (HLEQ); and to examine the characteristics of the HLE and the HLE profiles using the new instrument in the Greek educational context. The HLEQ is a parent-reported measure addressing both activities and interactions, comprising of six factors that are considered key elements of the HLE: indoor, outdoor, and digital learning activities, warmth/support, conflict, and inconsistent discipline. The development of HLEQ followed a robust methodological approach, including the collection of an initial pool of items, expert review to examine its content validity, and piloting. The HLEQ was administrated to 814 parents (Mage = 37.86 years, SD = 4.84) of children (Mage = 64.12 months, SD = 7.19) attending 84 state funded kindergartens in Greece. A cross-validation approach was used to examine the factor structure of the HLEQ. Exploratory and confirmatory factor analysis and exploratory structural equation modeling procedures were implemented. Latent profile analysis was employed to identify the HLE profiles. Results provided initial support for the factor structure, reliability, and validity of the HLEQ. The HLEQ displayed good psychometric properties for measuring the quality of home learning activities and home learning interactions in the contemporary early HLE. Four HLE profiles were revealed, representing different parent-child interaction patterns during the learning activities. Limitations and implications for policy and practice are discussed.

Use of a brief, retrospective Comprehensive Feeding Practices Questionnaire in a bariatric-surgery seeking adult population

Parental feeding practices in childhood have been shown to contribute to childhood eating habits, behaviors, and weight status. Less understood is the longitudinal impact of parental feeding practices on these variables in adulthood. Therefore, the aim of the present work was to validate a modified, brief, Comprehensive Feeding Practices Questionnaire (CFPQ) reformatted to account for retrospective recollections of parental feeding practices experienced in childhood among a sample of adults with obesity. Adults (n = 719, mean age = 44.3 years, mean BMI = 47.1 kg/m2) completed a modified, brief, retrospective CFPQ containing seven pre-defined subscales of the original CFPQ. Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) procedures were used to evaluate survey factor structure and associations with gender, BMI, and self-reported race. An EFA derived six-factor model demonstrated better model fit and reliability than the originally proposed seven-factor model. Gender and self-reported race were not correlated with subscales of the brief, retrospective, CFPQ, while BMI was positively correlated with the Food as Reward subscale. This six-factor, brief, retrospective, CFPQ can be used to provide insight into the potential origins of individual eating behaviors, and warrants use in future work attempting to clarify the relationships between parental feeding practices and eating behaviors in adulthood.

Scale Development of Social Support in the Vocational High School Context

The present study demonstrated scale development of the social support (SS), whose measurement should be re-evaluated based on past studies findings. This study aimed for scale development and investigated the dimensionality of items measuring the SS construct. The validation for content and face validity used Modified Delphi Method with seven panelists, however the Exploratory Factor Analysis (EFA) used questionnaires for construct validity and was administered on 100 students in 23 vocational high schools (VHS) as the sampling of this study. A total of 30 initial items were analyzed using Content Validity Index (CVI) that consisted of I-CVI and S-CVI, and was also analyzed with Fleiss Kappa Index (FKI). However, the 25 items were used to collect data in the study, which was then processed using SPSS version 24 on the EFA procedure. The SS-values instrument was found valid. This study's findings could serve as a basis for future research in this area as contribution reliable, and recommended in other relevant studies.

Grouping of mood symptoms by time series dynamics

BackgroundUnderstanding how symptoms of mood disorders vary over time in relation to each other is potentially valuable for diagnosis and predicting episodes of illness. In this paper, we characterize the degree of similarity of time series of different mood disorder symptoms. MethodsWe collected 32,215 mood disorder symptom questionnaires, administered twice-daily over 18 months to (n = 19) subjects with rapidly cycling bipolar disorder and (n = 20) healthy control subjects, using visual analog scales to rate 11 sets of symptom severity ratings plus a control item. We used Dynamic Time Warping to calculate similarity ratings between all within-subject pairs of severity ratings followed by Exploratory Factor Analysis (EFA) to identify latent factors of symptom time series across all subjects. ResultsTwo latent factors were identified: one with depression and anxiety; and a second, with concentration, energy, irritability, fatigue, appetite, euphoria/elation and overall mood. Restlessness, racing thoughts, and the control item (daily hours of daylight) did not cluster with any of the others. LimitationsLimited sample size dictated that we pool bipolar and healthy patients and use an iterative EFA procedure. ConclusionThis analysis suggests that, in a pooled sample of individuals with bipolar disorder and in healthy controls, severity ratings of overall depression and overall anxiety vary jointly as one dynamic factor, while some but not all other DSM mood symptoms vary jointly along with overall mood rating as a second dynamic factor. Further investigation may determine if these findings can simplify subjective symptom reporting in mood-monitoring studies.