Reliability and Validity of the Transport and Physical Activity Questionnaire (TPAQ) for Assessing Physical Activity Behaviour Emma J. Adams 1 *, Mary Goad 1 , Shannon Sahlqvist 2 , Fiona C. Bull 3 , Ashley R. Cooper 4 , David Ogilvie 5 on behalf of the iConnect Consortium 1 British Heart Foundation National Centre for Physical Activity and Health, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom, 2 Centre for Physical Activity and Nutrition Research (C-PAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia, 3 Centre for the Built Environment and Health, School of Population Health, University of Western Australia, Perth, Australia, 4 Centre for Exercise, Nutrition and Health Sciences, School for Policy Studies, University of Bristol, Bristol, United Kingdom, 5 Medical Research Council Epidemiology Unit and UKCRC Centre for Diet and Activity Research (CEDAR), University of Cambridge, Cambridge, United Kingdom Abstract Background: No current validated survey instrument allows a comprehensive assessment of both physical activity and travel behaviours for use in interdisciplinary research on walking and cycling. This study reports on the test-retest reliability and validity of physical activity measures in the transport and physical activity questionnaire (TPAQ). Methods: The TPAQ assesses time spent in different domains of physical activity and using different modes of transport for five journey purposes. Test-retest reliability of eight physical activity summary variables was assessed using intra-class correlation coefficients (ICC) and Kappa scores for continuous and categorical variables respectively. In a separate study, the validity of three survey-reported physical activity summary variables was assessed by computing Spearman correlation coefficients using accelerometer-derived reference measures. The Bland-Altman technique was used to determine the absolute validity of survey-reported time spent in moderate-to-vigorous physical activity (MVPA). Results: In the reliability study, ICC for time spent in different domains of physical activity ranged from fair to substantial for walking for transport (ICC = 0.59), cycling for transport (ICC = 0.61), walking for recreation (ICC = 0.48), cycling for recreation (ICC = 0.35), moderate leisure-time physical activity (ICC = 0.47), vigorous leisure-time physical activity (ICC = 0.63), and total physical activity (ICC = 0.56). The proportion of participants estimated to meet physical activity guidelines showed acceptable reliability (k = 0.60). In the validity study, comparison of survey-reported and accelerometer-derived time spent in physical activity showed strong agreement for vigorous physical activity (r = 0.72, p,0.001), fair but non-significant agreement for moderate physical activity (r = 0.24, p = 0.09) and fair agreement for MVPA (r = 0.27, p = 0.05). Bland-Altman analysis showed a mean overestimation of MVPA of 87.6 min/week (p = 0.02) (95% limits of agreement 2447.1 to +622.3 min/week). Conclusion: The TPAQ provides a more comprehensive assessment of physical activity and travel behaviours and may be suitable for wider use. Its physical activity summary measures have comparable reliability and validity to those of similar existing questionnaires. Citation: Adams EJ, Goad M, Sahlqvist S, Bull FC, Cooper AR, et al. (2014) Reliability and Validity of the Transport and Physical Activity Questionnaire (TPAQ) for Assessing Physical Activity Behaviour. PLoS ONE 9(9): e107039. doi:10.1371/journal.pone.0107039 Editor: Conrad P. Earnest, Texas A&M University, United States of America Received January 11, 2014; Accepted August 11, 2014; Published September 12, 2014 Copyright: ß 2014 Adams et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The iConnect consortium is funded by the Engineering and Physical Sciences Research Council (grant reference EP/G00059X/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. DO is also supported by the Medical Research Council [Unit Programme number MC_UU_12015/6] and the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence that is funded by the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research and the Wellcome Trust. The views expressed in this paper are those of the authors and do not necessarily reflect those of the study funders, the NIHR, or the Department of Health. Competing Interests: The authors have declared that no competing interests exist. * Email: e.j.adams@lboro.ac.uk Introduction Current approaches for increasing population levels of physical activity include promoting walking and cycling for transport and recreation. This has the potential to support policy goals in a number of sectors including public health (increasing physical activity levels), transport (increasing the use of sustainable travel modes) and environment (reducing carbon emissions) [1–3]. Increasingly, interdisciplinary research teams are working together to advance research in this area and require comprehensive measures of physical activity and travel behaviours to meet their different needs [3–5]. These measures need to enable assessment of the frequency and duration of participation in specific domains of physical activity, the total amount of physical activity undertaken, and the time spent and distance travelled using PLOS ONE | www.plosone.org 1 September 2014 | Volume 9 | Issue 9 | e107039