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How we are misinterpreting physical activity intention – behavior relations and what to do about it

BACKGROUND: Studies of the physical activity intention-behavior gap, and factors that may moderate the gap (e.g., habit, perceived behavioral control), can inform physical activity promotion efforts. Yet, these studies typically apply linear modeling procedures, and so conclusions rely on linearity...

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Autores principales: Rebar, Amanda L., Rhodes, Ryan E., Gardner, Benjamin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704506/
https://www.ncbi.nlm.nih.gov/pubmed/31438956
http://dx.doi.org/10.1186/s12966-019-0829-y
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author Rebar, Amanda L.
Rhodes, Ryan E.
Gardner, Benjamin
author_facet Rebar, Amanda L.
Rhodes, Ryan E.
Gardner, Benjamin
author_sort Rebar, Amanda L.
collection PubMed
description BACKGROUND: Studies of the physical activity intention-behavior gap, and factors that may moderate the gap (e.g., habit, perceived behavioral control), can inform physical activity promotion efforts. Yet, these studies typically apply linear modeling procedures, and so conclusions rely on linearity and homoscedasticity assumptions, which may not hold. METHODS: We modelled and plotted physical activity intention-behavior associations and the moderation effects of habit using simulated data based on (a) normal distributions with no shared variance, (b) correlated parameters with normal distribution, and (c) realistically correlated and non-normally distributed parameters. RESULTS: In the uncorrelated and correlated normal distribution datasets, no violations were unmet, and the moderation effects applied across the entire data range. However, because in the realistic dataset, few people who engaged in physical activity behavior had low intention scores, the intention-behavior association was non-linear, resulting in inflated linear moderation estimations of habit. This finding was replicated when tested with intention-behavior moderation of perceived behavioral control. CONCLUSIONS: Comparisons of the three scenarios illustrated how an identical correlation coefficient may mask different types of intention-behavior association and moderation effects. These findings highlight the risk of misinterpreting tests of the intention-behavior gap and its moderators for physical activity due to unfounded statistical assumptions. The previously well-documented moderating effects of habit, whereby the impact of intention on behavior weakens as habit strength increases, may be based on statistical byproducts of unmet model assumptions.
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spelling pubmed-67045062019-08-22 How we are misinterpreting physical activity intention – behavior relations and what to do about it Rebar, Amanda L. Rhodes, Ryan E. Gardner, Benjamin Int J Behav Nutr Phys Act Research BACKGROUND: Studies of the physical activity intention-behavior gap, and factors that may moderate the gap (e.g., habit, perceived behavioral control), can inform physical activity promotion efforts. Yet, these studies typically apply linear modeling procedures, and so conclusions rely on linearity and homoscedasticity assumptions, which may not hold. METHODS: We modelled and plotted physical activity intention-behavior associations and the moderation effects of habit using simulated data based on (a) normal distributions with no shared variance, (b) correlated parameters with normal distribution, and (c) realistically correlated and non-normally distributed parameters. RESULTS: In the uncorrelated and correlated normal distribution datasets, no violations were unmet, and the moderation effects applied across the entire data range. However, because in the realistic dataset, few people who engaged in physical activity behavior had low intention scores, the intention-behavior association was non-linear, resulting in inflated linear moderation estimations of habit. This finding was replicated when tested with intention-behavior moderation of perceived behavioral control. CONCLUSIONS: Comparisons of the three scenarios illustrated how an identical correlation coefficient may mask different types of intention-behavior association and moderation effects. These findings highlight the risk of misinterpreting tests of the intention-behavior gap and its moderators for physical activity due to unfounded statistical assumptions. The previously well-documented moderating effects of habit, whereby the impact of intention on behavior weakens as habit strength increases, may be based on statistical byproducts of unmet model assumptions. BioMed Central 2019-08-22 /pmc/articles/PMC6704506/ /pubmed/31438956 http://dx.doi.org/10.1186/s12966-019-0829-y Text en © The Author(s). 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Rebar, Amanda L.
Rhodes, Ryan E.
Gardner, Benjamin
How we are misinterpreting physical activity intention – behavior relations and what to do about it
title How we are misinterpreting physical activity intention – behavior relations and what to do about it
title_full How we are misinterpreting physical activity intention – behavior relations and what to do about it
title_fullStr How we are misinterpreting physical activity intention – behavior relations and what to do about it
title_full_unstemmed How we are misinterpreting physical activity intention – behavior relations and what to do about it
title_short How we are misinterpreting physical activity intention – behavior relations and what to do about it
title_sort how we are misinterpreting physical activity intention – behavior relations and what to do about it
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704506/
https://www.ncbi.nlm.nih.gov/pubmed/31438956
http://dx.doi.org/10.1186/s12966-019-0829-y
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