Imputation of Missing Data When Measuring Physical Activity by Accelerometry

Catellier, Diane J.; Hannan, Peter J.; Murray, David M.; Addy, Cheryl L.; Conway, Terry L.; Yang, Song; Rice, Janet C.

doi:10.1249/01.mss.0000185651.59486.4e

Cited by 339 publications

(361 citation statements)

References 20 publications

(18 reference statements)

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“…The first step utilizes approaches for dealing with missing data. These analyses follow the general methodology proposed for dealing with missing accelerometer data in a previous national trial [62], in which multiple imputation is used to provide unbiased parameter estimates and standard errors for the treatment effect. Each day of Actical data is be divided into five intervals -6-9 am, 9-2 pm, 2-5 pm, 5-8pm, and 8 pm to midnight -and the average rate of PA is be computed for each interval.…”

Section: Data Analyses Plan For Primary Outcomementioning

confidence: 99%

“…Each day of Actical data is be divided into five intervals -6-9 am, 9-2 pm, 2-5 pm, 5-8pm, and 8 pm to midnight -and the average rate of PA is be computed for each interval. Following the previous national multi-site trial procedures, a student's data is considered missing for a given time period if they wore the accelerometer less than 80% of the time that 70% of the students wore their accelerometers [62]. Data for the baseline, midpoint, and posttest time periods is imputed simultaneously along with indicators of treatment condition, school, and other baseline covariates.…”

Section: Data Analyses Plan For Primary Outcomementioning

confidence: 99%

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An overview of “The Active by Choice Today” (ACT) trial for increasing physical activity

Wilson

Kitzman-Ulrich

Williams

et al. 2008

Contemporary Clinical Trials

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Background: Although school-based behavioral interventions for increasing physical activity (PA) in children and adolescents have been conducted, little evidence suggests that these curriculum-based approaches lead to increases in overall activity outside of program days. The overall goal of the "Active by Choice Today" (ACT) trial is to expand the body of knowledge concerning the factors that influence long-term increases in PA in underserved adolescents (low socioeconmic status, minorities) during their middle school years. Design and setting:An overview of the ACT study design, theoretical framework, process evaluation, and primary hypotheses is presented. The trial involves twenty-four middle schools (1560 6th graders) in South Carolina that are randomly assigned to one of two after-school programs (motivational and life skills intervention, or general health education). Intervention:The intervention integrates constructs from Self-Determination and Social Cognitive Theories to enhance intrinsic motivation and behavioral skills for PA. The intervention targets skill development for PA outside of program days and the after-school program social environment Publisher's Disclaimer: This article was published in an Elsevier journal. The attached copy is furnished to the author for non-commercial research and education use, including for instruction at the author's institution, sharing with colleagues and providing to institution administration. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. (autonomy, choice, participation, belongingness, fun, enjoyment, support) is designed to positively impact cognitive mediators (self-efficacy, perceived competence), and motivational orientation (intrinsic motivation, commitment, positive self-concept). NIH Public Access Main hypotheses/outcomes:It is hypothesized that the 17-week motivational and life skills intervention will lead to greater increases in moderate-to-vigorous PA (based on 7-day accelerometry estimates) at post-intervention as compared to the general health education program. Conclusions:Implications of this innovative school-based trial are discussed.

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Section: Data Analyses Plan For Primary Outcomementioning

confidence: 99%

Section: Data Analyses Plan For Primary Outcomementioning

confidence: 99%

An overview of “The Active by Choice Today” (ACT) trial for increasing physical activity

Wilson

Kitzman-Ulrich

Williams

et al. 2008

Contemporary Clinical Trials

Self Cite

View full text Add to dashboard Cite

show abstract

“…19 We considered data sufficiently complete if at least 80% of the data expected to be collected on each measurement day were valid. The probability of having one or more incomplete days of accelerometer data was not associated with race, age, or average activity based on completely observed days.…”

Section: Instrumentation and Data Collectionmentioning

confidence: 99%

Comparing Perceived and Objectively Measured Access to Recreational Facilities as Predictors of Physical Activity in Adolescent Girls

et al. 2007

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A number of studies in recent years have identified both self-report and objectively measured accessibility of recreational facilities as important predictors of physical activity in youth. Yet, few studies have: (1) examined the relationship between the number and proximity of objectively measured neighborhood physical activity facilities and respondents_ perceptions and (2) compared objective and self-report measures as predictors of physical activity. This study uses data on 1,367 6th-grade girls who participated in the Trial of Activity for Adolescent Girls (TAAG) to explore these issues. Girls reported whether nine different types of recreational facilities were easily accessible. These facilities included basketball courts, golf courses, martial arts studios, playing fields, tracks, skating rinks, swimming pools, tennis courts, and dance/ gymnastic clubs. Next, geographic information systems (GIS) were used to identify all the parks, schools, and commercial sites for physical activity located within a mile of each girl_s home. These sites were then visited to inventory the types of facilities available. Girls wore accelerometers to measure their weekly minutes of non-school metabolic equivalent weighted moderate-to-vigorous physical activity (MW-MVPA). The number of facilities within a half-mile of girls_ homes strongly predicted the perception of easy access to seven out of nine facility types. Both individual facility perceptions and the total number of facilities perceived were associated with increased physical activity. For each additional facility perceived, girls clocked 3% more metabolic equivalent weighted moderate-to-vigorous physical activity (pG0.001). Although girls tended to record 3% more of this kind of physical activity (pG0.05) per basketball court within a mile of their homes, objective facility measures were otherwise unrelated to physical activity. The results from this study suggest that raising the profile of existing facilities may help increase physical activity among adolescent girls.

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“…Readings at or above 1500 counts/30 s were treated as MVPA . Occasional missing data within a girl's 6-day record were replaced via imputation based on the Expectation Maximization (EM) algorithm (Catellier et al, 2005). Counts above 1500/30 s were converted into METs (metabolic equivalents) using a regression equation (corresponding to 4.6 METS) (Schmitz et al, 2005).…”

Section: Measurement Of Physical Activitymentioning

confidence: 99%

Commercial venues as supports for physical activity in adolescent girls

Dowda

McKenzie

Cohen

et al. 2007

Preventive Medicine

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Objective-The purposes of this study were to describe the types and availability of commercial facilities for physical activity (PA) in six diverse geographic areas (Washington DC and Maryland; South Carolina; Minnesota; Louisiana; Arizona; and California) and to assess the relationship between those facilities and the non-school PA of adolescent girls.Methods-A total of 1556 6th grade girls participating in the Trial of Activity for Adolescent Girls (TAAG) wore accelerometers for 7 days providing 6 days of complete data, completed questionnaires in 2003 and had their residential addresses geocoded. Nearby commercial facilities available to provide PA (i.e. dance studios, youth organizations) within a 1-mile radius of participants' residences were identified and geocoded. The association between the presence of any commercial PA facility and girls' PA was determined using a multi-level design and controlling for demographic characteristics and other potential confounders. Analyses were conducted in 2005-2006. Results-Sixty-eight percent of the girls had at least one commercial PA facility near their homes. Availability and types of commercial PA facilities differed by where participants lived. Girls who lived near one or more commercial PA facilities had higher non-school MET-weighted moderateto-vigorous PA than girls who had none near their homes.Conclusions-The findings suggest that commercial PA facilities are important contributors to the accumulation of PA among adolescent girls.

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Imputation of Missing Data When Measuring Physical Activity by Accelerometry

Abstract: Researchers are encouraged to take advantage of software to implement missing value imputation, as estimates of activity are more precise and less biased in the presence of intermittent missing accelerometer data than those derived from an observed data analysis approach.

Cited by 339 publications

References 20 publications

An overview of “The Active by Choice Today” (ACT) trial for increasing physical activity

An overview of “The Active by Choice Today” (ACT) trial for increasing physical activity

Comparing Perceived and Objectively Measured Access to Recreational Facilities as Predictors of Physical Activity in Adolescent Girls

Commercial venues as supports for physical activity in adolescent girls

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