Medicine and Health Sciences Commons^™

Validation Of Accelerometer For Measuring Physical Activity In Free-Living Individuals, George O. Agogo, Hilko Van Der Voet, Paul J.M. Hulshof, Pieter Van ’T Veer, Laura Trijsburg, Fred A. Van Eeuwijk, Hendriek C. Boshuizen

Baltic Journal of Health and Physical Activity

Background: The aim of this research was to validate a triaxial GT3X accelerometer against doubly labelled water for measuring total energy expenditure (TEE) in a study of free-living Dutch adults and to compare the two prediction equations used to calculate accelerometer derived activity related energy expenditure. Material/Methods: We used a measurement error model to estimate bias in the mean TEE, a correlation coefficient between measured and true TEE (a validity coefficient, which quantifies loss of statistical power to detect association) and the attenuation factor (which quantifies bias in the association), with and without conditioning on age, sex and BMI. We …

Consistency Of Ever Reported Risky And Sensitive Behaviors Among Early Adolescents In A Nationally Representative Longitudinal Study: Results From The First 2 Waves Of The Longitudinal Cohort Study Of The Filipino Child, 2016 To 2018, Nel Jason L. Haw

Health Sciences Faculty Publications

Background: An ongoing cohort study on adolescents in the Philippines presents a unique opportunity to update current literature by measuring the level of reporting consistency on these behaviors and determine predictors of reporting inconsistency.

Methods: This study was a secondary analysis of the first 2 waves of the Longitudinal Cohort Study on the Filipino Child (LCSFC), a nationally representative cohort of Filipino adolescents throughout the Sustainable Development Goals (SDGs) implementation period, that is, age 10 in 2015 until age 24 in 2030, to measure the impact of SDG-oriented policies on the country’s future economic and health outcomes. This …

Measurement Precision And Reliability Of Supraspinatus Tendon Strain Using Speckle Track Analysis Of Ultrasound Images, Gregory Alan Mcclanahan

Theses, Dissertations and Capstones

Introduction: Ultrasound speckle tracking is an emergent method in studying musculoskeletal physiology and disease. For a method to be effective and useful, it needs to be precise and reliable. The precision and reliability of supraspinatus tendon strain measurements have not been explored. The purpose of this study was to examine the precision and reliability of speckle tracking to measure supraspinatus tendon strain.

Methods: Forty-two (42) participants participated in this study. Five (5) ultrasound images of the participant’s right shoulder supraspinatus tendon were collected during a maximal voluntary isometric abduction contraction. Cine loop video files of the 5 imaging trials …

A Spline-Assisted Semiparametric Approach To Nonparametric Measurement Error Models, Fei Jiang, Yanyuan Ma

COBRA Preprint Series

Nonparametric estimation of the probability density function of a random variable measured with error is considered to be a difficult problem, in the sense that depending on the measurement error prop- erty, the estimation rate can be as slow as the logarithm of the sample size. Likewise, nonparametric estimation of the regression function with errors in the covariate suffers the same possibly slow rate. The traditional methods for both problems are based on deconvolution, where the slow convergence rate is caused by the quick convergence to zero of the Fourier transform of the measurement error density, which, unfortunately, appears in …

Parts Of The Whole: Error Estimation For Science Students, Dorothy Wallace

Numeracy

It is important for science students to understand not only how to estimate error sizes in measurement data, but also to see how these errors contribute to errors in conclusions they may make about the data. Relatively small errors in measurement, errors in assumptions, and roundoff errors in computation may result in large error bounds on computed quantities of interest. In this column, we look closely at a standard method for measuring the volume of cancer tumor xenografts to see how small errors in each of these three factors may contribute to relatively large observed errors in recorded tumor volumes.

Evaluating Predictors Of An Individual’S Dietary Intake Latent Value Under Different Mixed Models, Shuli Yu

Doctoral Dissertations

The accurate estimation of an individual’s usual dietary intake is important since the estimates are essential to uncover the diet-disease relationships. This study explores a more accurate method to estimate an individual’s latent value of usual dietary intake when it is repeatedly measured using a 24-hour dietary recall (24HR) and seven day dietary recall (7DDR), accounting for random measurement error and bias. The performance of the (empirical) predictor of subject’s latent value obtained under the finite population mixed model (FPMM) framework is compared with those obtained under the usual mixed model and the measurement error model through a simulation study. …

Identifying And Addressing Sources Of Measurement Error In The Norbeck Social Support Questionnaire, Eileen Gigliotti, William Ellery Samuels, June Como, Tofiga Gamidova, Brian Gordon, Peter Acerios

Publications and Research

Background and Purpose: The Norbeck Social Support Questionnaire (NSSQ) provides a rich portrait of one’s perceived social support including network size/composition and quality of support. Analyses of quantitative research reports and critiques of the NSSQ revealed non-negligible measurement error. We document evidence of measurement error, report potential sources of this error, and present forthcoming psychometric testing. Methods: Quantitative evidence of measurement error from the NSSQ literature provided the basis for initial hypotheses concerning sources of error in network nomination and support ratings. We then conducted cognitive interviews to investigate these hypotheses. Results: Cognitive interviews revealed evidence of respondents’ miscomprehension and …

Reliability And Measurement Error In Using A Tape Measure To Determine Limb Circumference, Ching-Yi Wang, Chin-Lin Hsieh, Sheng-Kuang Wu, Chu-Kuei Chang, Chiew-Ju Hsish, Chien-Fen Lin

Rehabilitation Practice and Science

The purposes of this study were (1) to test the inter-rater and intra-rater reliability of using a tape measure to determine limb circumferences and (2) to report the 95% CI of standard error of measurement (SEM) of repeated measures by the same tester to determine whether a clinically important change has occurred.Forty-six college students (6 men, 40 women) with a mean age of 20 years old volunteered to participate in this study. Subjects reported no neuro-musculo-skeletal diseases or disorders in their upper or lower extremities. To determine the inter-rater reliability, two testers measured the circumference of 4 locations on the …

On Corrected Score Approach For Proportional Hazards Model With Covariate Measurement Error, Xiao Song, Yijian Huang

UW Biostatistics Working Paper Series

In the presence of covariate measurement error with the proportional hazards model, several functional modeling methods have been proposed. These include the conditional score estimator (Tsiatis and Davidian, 2001), the parametric correction estimator (Nakamura, 1992) and the nonparametric correction estimator (Huang and Wang, 2000, 2003) in the order of weaker assumptions on the error. Although they are all consistent, each suffers from potential difficulties with small samples and substantial measurement error. In this article, upon noting that the conditional score and parametric correction estimators are asymptotically equivalent in the case of normal error, we investigate their relative finite sample performance …

A Corrected Pseudo-Score Approach For Additive Hazards Model With Longitudinal Covariates Measured With Error, Xiao Song, Yijian Huang

UW Biostatistics Working Paper Series

In medical studies, it is often of interest to characterize the relationship between a time-to-event and covariates, not only time-independent but also time-dependent. Time-dependent covariates are generally measured intermittently and with error. Recent interests focus on the proportional hazards framework, with longitudinal data jointly modeled through a mixed effects model. However, approaches under this framework depend on the normality assumption of the error, and might encounter intractable numerical difficulties in practice. This motivates us to consider an alternative framework, that is, the additive hazards model, under which little has been done when time-dependent covariates are measured with error. We propose …