NO NORMALIDAD Y HETEROGENEIDAD DE VARIANZA EN EL MODELO LINEALMIXTO (MLM) EN DISEÑOS SPLIT-PLOTCON MUESTRAS PEQUEÑAS

Los datos provenientes de investigaciones de tipo longitudinal en psicología suelen reflejar condiciones características de este ámbito de estudio, como son los tamaños muestrales reducidos, distribuciones no normales, violaciones de los supuestos de esfericidad y homogeneidad de varianza. Actualmente, el modelo lineal mixto (MLM) es uno de los procedimientos más recomendados cuando los supuestos en los que se basan los procedimientos tradicionales no se cumplen. Cuando los tamaños muestrales son reducidos se suele utilizar algún procedimiento de ajuste de los grados de libertad que mejore las propiedades del MLM, como el propuesto por Kenward y Roger (KR; 1997). El objetivo de este estudio fue ampliar el estudio realizado por Arnau et al. (2011) evaluando la robustez de KR con diseños split-plot de muestras pequeñas ante violaciones de la normalidad en diferente grado en los distintos grupos, violaciones de la esfericidad y de la homogeneidad de varianza. Se realiza un estudio de simulación Monte Carlo considerando un diseño split-plot con 3 grupos y 4 ocasiones de medidas repetidas, con tamaños muestrales totales de 36 y 42 individuos, asumiendo una matriz de covarianza no estructurada en la generación de datos. Se han manipulado las siguientes condiciones: a) con grupos balanceados y no balanceados; b) homogeneidad y heterogeneidad de la matriz de covarianza; c) emparejamiento nulo, positivo o negativo entre el tamaño de grupo y la matriz de covarianza y d) esfericidad de 0,57 ó 0,75. Los resultados muestran que KR es robusto cuando los diseños son equilibrados, independientemente de la violación de los supuestos de esfericidad y/o de homogeneidad de varianza. Sin embargo, cuando los diseños no son equilibrados, se halla una tendencia a la liberalidad, especialmente cuando el emparejamiento de las matrices de covarianza y el tamaño de los grupos es negativo. Los resultados de este estudio van en la línea con los obtenidos en estudios previos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto de Investigación PSI2012-32662 Ministerio Economía y Competitividad

The effect of skewness and kurtosis on the Kenward-Roger approximation when group distributions differ

This study examined the independent effect of skewness and kurtosis on the robustness of the linear mixed model (LMM), with the Kenward-Roger (KR) procedure, when group distributions are different, sample sizes are small, and sphericity cannot be assumed. Methods: A Monte Carlo simulation study considering a split-plot design involving three groups and four repeated measures was performed. Results: The results showed that when group distributions are different, the effect of skewness on KR robustness is greater than that of kurtosis for the corresponding values. Furthermore, the pairings of skewness and kurtosis with group size were found to be relevant variables when applying this procedure. Conclusions: With sample sizes of 45 and 60, KR is a suitable option for analyzing data when the distributions are: (a) mesokurtic and not highly or extremely skewed, and (b) symmetric with different degrees of kurtosis. With total sample sizes of 30, it is adequate when group sizes are equal and the distributions are: (a) mesokurtic and slightly or moderately skewed, and sphericity is assumed; and (b) symmetric with a moderate or high/extreme violation of kurtosis. Alternative analyses should be considered when the distributions are highly or extremely skewed and samples sizes are small

Comparison of the procedures of Fleishman and Ramberg et al. for generating non normal data in simulation studies

Simulation techniques must be able to generate the types of distributions most commonly encountered in real data, for example, non-normal distributions. Two recognized procedures for generating non-normal data are Fleishman's linear transformation method and the method proposed by Ramberg et al. that is based on generalization of the Tukey lambda distribution. This study compares these procedures in terms of the extent to which the distributions they generate fit their respective theoretical models, and it also examines the number of simulations needed to achieve this fit. To this end, the paper considers, in addition to the normal distribution, a series of non-normal distributions that are commonly found in real data, and then analyses fit according to the extent to which normality is violated and the number of simulations performed. The results show that the two data generation procedures behave similarly. As the degree of contamination of the theoretical distribution increases, so does the number of simulations required to ensure a good fit to the generated data. The two procedures generate more accurate normal and non-normal distributions when at least 7000 simulations are performed, although when the degree of contamination is severe (with values of skewness and kurtosis of 2 and 6, respectively) it is advisable to perform 15000 simulations

Spanish version of the Phubbing Scale:Internet addiction, Facebook intrusion, and fear of missing out as correlates

BACKGROUND:Phubbing is an increasingly common behavior that involves using a smartphone in a social setting of two or more people and interacting with the phone rather than with the other people. Research to date on phubbing has measured it using different scales or single questions, and therefore standard measures with appropriate psychometric properties are needed to improve its assessment. The aim of our study was to develop a Spanish version of the Phubbing Scale and to examine its psychometric properties: factor structure, reliability, and concurrent validity.METHOD:Participants were 759 Spanish adults between 18 and 68 years of age. They completed an online survey.RESULTS:The results support a structure that is consistent with the original validation study, with two factors: Communication Disturbance and Phone Obsession. Internal consistency was found to be adequate. Evidence of concurrent validity was provided via a hierarchical regression model that showed positive associations with measures of internet addiction, Facebook intrusion, and fear of missing out.CONCLUSIONS:These results indicate that the Spanish version of the Phubbing Scale exhibits appropriate psychometric properties

Social support from the closest person and sleep quality in later life: evidence from a British birth cohort study

ObjectivesSupportive social relationships have been found to be related to fewer sleep problems and better sleep quality. We examined associations between positive and negative support from the nominated close person across 15 years of follow-up with sleep quality in older age.MethodsMRC National Survey of Health and Development study members reported sleep quality at age 68 (n = 2446). Cumulative exposure to and changes in positive and negative support were derived from data at age 53, 60–64 and 68 years. Pittsburgh Sleep Quality Index scores were regressed on social support measures adjusted for i) gender only then additionally ii) education, marital status, number in household, limiting illness, body mass index, caregiving, iii) and affective symptoms.ResultsGreater exposure to positive support and lower exposure to negative support over 15 years were independently associated with better sleep quality at age 68. Sleep quality was poorer for those who experienced declining positive support or increasing negative support. Those who nominated their spouse/partner as their closest person at age 53 but not at age 68 had poorer sleep quality than those who nominated their spouse on both occasions. These associations were not explained by the covariates, including affective symptoms.ConclusionsBased on repeat data on support from the closest person, this study finds a link between declining social relationship quality and poor sleep quality. Whilst acknowledging that the association may be bi-directional, the study suggests that interventions to improve older people's social relationships may have benefits for sleep

Versión española de la Escala de Phubbing: adicción a Internet, intrusión de Facebook y miedo a perderse algo como correlatos

Background: Phubbing is an increasingly common behavior that involves using a smartphone in a social setting of two or more people and interacting with the phone rather than with the other people. Research to date on phubbing has measured it using different scales or single questions, and therefore standard measures with appropriate psychometric properties are needed to improve its assessment. The aim of our study was to develop a Spanish version of the Phubbing Scale and to examine its psychometric properties: factor structure, reliability, and concurrent validity. Method: Participants were 759 Spanish adults between 18 and 68 years of age. They completed an online survey. Results: The results support a structure that is consistent with the original validation study, with two factors: Communication Disturbance and Phone Obsession. Internal consistency was found to be adequate. Evidence of concurrent validity was provided via a hierarchical regression model that showed positive associations with measures of internet addiction, Facebook intrusion, and fear of missing out. Conclusions: These results indicate that the Spanish version of the Phubbing Scale exhibits appropriate psychometric properties.Antecedentes: el incremento del uso de los teléfonos móviles ha derivado en el incremento del phubbing, que se define como la conducta de ignorar a otras personas durante una interacción social por el uso del teléfono móvil. El objetivo de este estudio es desarrollar y validar la escala de Phubbing en su versión española y examinar sus propiedades psicométricas: estructura factorial, fiabilidad y validez concurrente. Método: se administró una batería de tests a 759 adultos españoles entre 18 y 68 años. Resultados: los resultados mostraron una estructura de dos factores consistente con la versión original: Disrupción de la comunicación y Obsesión con el teléfono móvil. La consistencia interna fue adecuada y las evidencias de validez concurrente, mediante regresión jerárquica, mostraron correlaciones positivas con medidas de adicción a Internet, adicción a Facebook y miedo a perderse algo (FoMO). Conclusiones: la escala de Phubbing en su versión española muestra adecuadas propiedades psicométricas

Versión española del Cuestionario de Intrusión del Facebook (FIQ-S)

Background: Although there is growing research on the excessive use of Facebook and its correlates, most studies to date are not directly comparable or generalizable to the overall population as their samples are often limited to students and they use different assessment tools. The first aim of our study was to develop a Spanish version of the Facebook Intrusion Questionnaire (FIQ-S), an instrument which emphasises the social components and consequences of excessive Facebook use. Second, we aimed to examine its psychometric properties: factor structure, reliability and external validity. Methods: Participants were 567 Spanish adults who completed an online battery of questionnaires, including variables related to addictive behaviours. Results: Exploratory and confirmatory factor analysis, using a cross-validation strategy, supported a one-factor structure. The composite reliability value was adequate. Evidence of external validity was provided via correlational analysis, showing a negative association with self-control and positive associations with time spent using social networking sites, problematic mobile phone use, internet addiction, phubbing, fear of missing out and depression. Conclusions: Results are consistent with the original validation study and confirm the addictive component of the construct measured and highlight the impact of Facebook abuse on mental health.Antecedentes: a pesar de que está aumentando la investigación sobre el uso excesivo de Facebook y sus correlatos, la mayoría de los estudios no son directamente comparables o generalizables a la población general ya que sus muestras suelen ser de estudiantes y usan diferentes instrumentos de evaluación. El primer objetivo es desarrollar la versión española del Cuestionario de Intrusión del Facebook (FIQ-S). Este instrumento enfatiza los componentes y consecuencias sociales del uso excesivo del Facebook. El segundo objetivo es examinar sus propiedades psicométricas: estructura factorial, fiabilidad y validez externa. Método: los participantes fueron 567 adultos españoles, quienes completaron una batería de cuestionarios online. Resultados: los análisis factoriales exploratorios y confirmatorios, con validación cruzada, muestran una estructura unifactorial. La fiabilidad compuesta es adecuada. Los análisis de las correlaciones muestran evidencias de validez externa, encontrándose asociaciones negativas con autocontrol y positivas con tiempo de uso de las redes sociales, uso problemático del teléfono móvil, phubbing, adicción a internet, miedo a perderse algo y depresión. Conclusiones: los resultados son consistentes con el estudio de validación de la versión original y confirman el componente adictivo del constructo evaluado. Además, se destaca el impacto del uso excesivo de Facebook en salud mental

Lifetime socioeconomic circumstances and chronic pain in later adulthood:findings from a British birth cohort study

OBJECTIVES: To investigate associations between a range of different indicators of socioeconomic position (SEP: occupational class, education, household overcrowding and tenure, and experience of financial hardship) across life and chronic widespread and regional pain (CWP and CRP) at age 68.DESIGN: Prospective birth cohort; the Medical Research Council National Survey of Health and Development.SETTING: England, Scotland and Wales.PARTICIPANTS: Up to 2378 men and women who have been followed-up since birth in 1946 to age 68.PRIMARY OUTCOME MEASURES: On the basis of their self-report of pain at age 68, participants were classified as: CWP (American College of Rheumatology criteria), CRP (pain of at least 3 months' duration but that does not meet the definition of CWP), other pain (&lt;3 months in duration) or no pain.RESULTS: At age 68, the prevalence of CWP was 13.3% and 7.8% in women and men, respectively, and that of CRP was 32.3% and 28.7% in women and men, respectively. There was no clear evidence that indicators of SEP in childhood or later adulthood were associated with pain. Having experienced (vs not) financial hardship and being a tenant (vs owner-occupier) in earlier adulthood were both associated with an increased risk of CWP; for example, moderate hardship adjusted relative risk ratio (RRR adj) 2.32 (95% CI: 1.19 to 4.52) and most hardship RRR adj 4.44 (95% CI: 2.02 to 9.77). Accumulation of financial hardship across earlier and later adulthood was also associated with an increased risk of CWP. CONCLUSIONS: Consideration of socioeconomic factors in earlier adulthood may be important when identifying targets for intervention to prevent CWP in later life.</p

MedCATTrainer: A Biomedical Free Text Annotation Interface with Active Learning and Research Use Case Specific Customisation

We present MedCATTrainer an interface for building, improving and customising a given Named Entity Recognition and Linking (NER+L) model for biomedical domain text. NER+L is often used as a first step in deriving value from clinical text. Collecting labelled data for training models is difficult due to the need for specialist domain knowledge. MedCATTrainer offers an interactive web-interface to inspect and improve recognised entities from an underlying NER+L model via active learning. Secondary use of data for clinical research often has task and context specific criteria. MedCATTrainer provides a further interface to define and collect supervised learning training data for researcher specific use cases. Initial results suggest our approach allows for efficient and accurate collection of research use case specific training data