A shift towards integrating mobility in place and health research is occurring. That is, researchers are increasingly interested in understanding people’s spatial behaviour and their daily activity settings when studying the influence of environmental resources on health. This mobility shift extends existing research which often focuses solely on residential neighbourhoods. It stems from evidence indicating that people visit a diversity of places in their daily lives and that each of these locations may influence their health in unique ways [1, 2].
Given that people are mobile, exposures in a variety of places in addition to residential neighbourhoods should be assessed when accounting for environmental influences on health. Environmental conditions, resources, and opportunities available in residential areas differ considerably from those measured in people’s other activity settings [3–6]. For example, Kestens et al. (2010) found that the average fast food outlet density in daily activity locations was twice that measured in residential neighbourhoods . Characteristics of activity settings have also been shown to modify or confound the association between residential neighbourhoods and health . In a study by Inagami et al. (2007), adjusting for non-residential deprivation reinforced the inverse relationship between residential deprivation and self-rated health . Since contextual measures and research findings may be sensitive to different spatial delineations of context [8, 9], integrating mobility and people’s regular activity locations, also known as their activity space , in place and health research merits further exploration.
Towards this end, several data collection tools are available such as travel or activity diaries, travel surveys, global positioning systems (GPS), and activity location questionnaires. Travel diaries require participants to register detailed information on all trips (location of origins and destinations, start and end times, purpose, etc.) for a given period of time in a diary. Although the information gathered and the timeframe covered (which has ranged from two days  to multiple weeks ) can be adapted to one’s research question, travel diaries are time consuming and impose a heavy burden on participants. As well, short observation periods preclude collection of routinely but less frequently visited locations. Data collected using diaries may also deviate systematically from actual behaviour since respondents tend to underreport small trips and trips that do not start or end at home .
Stemming from the field of transportation research, travel surveys have also been used in place and health research [4, 5]. They consist of Computer- or Web- Assisted Telephone Interviews to recall trips made by an individual over a given period, usually 24 hours, preceding the interview. Contrary to travel diaries which are generally used in small samples, travel surveys can be used in very large samples. However, they can exclude important activity locations which were not visited the day preceding the interview, and thus only partially represent one’s regular activity space [4, 5, 13].
An alternative to travel diaries and surveys resides in passive data collection tools such as GPS incorporated into cellular phones or sensors [12, 14–18]. GPS devices have the advantage of providing objective information on travel routes and activity locations. However, the limited time frame they normally cover (one to 10 days) and other issues such as compliance, limited battery performance, or losing the signal indoors may also preclude the identification of regular activity locations. Similarly, the amount of data collected can become overwhelming and data processing requires a high skill level even though novel GPS processing toolkits are being developed and disseminated .
Finally, various types of questionnaires have been used to collect information on the geographical location of people’s regular activity places. Going back as far as the 1950s , activity location questionnaires have been used in public health research [7, 21, 22]. Activity location questionnaires do not necessarily refer to a reference period but rather use specific activities such as work, studies, or shopping as the starting point from which to derive geographical information on regular activity patterns [7, 21]. Alternative forms of questionnaires may require participants to list and describe all the places where they spent time in a given time frame  or to report whether they usually undertake specified activities ‘mainly inside’ , ‘partly inside’ , or ‘mainly outside’ their residential neighbourhood [22, 24]. Activity location questionnaires are useful in providing a rapid assessment of places where people spend time. However, when not directly supported by interactive mapping tools, locational data such as addresses and cross streets may be difficult to transform into precise and valid geographic coordinates .
Thus, despite their relevance and increasing use in research on activity spaces and health, the psychometric properties of activity location questionnaires have not been examined. Poor validity in activity location reporting may lead to invalid assignment of environmental exposures based on these locations and subsequently undermine the validity of their associations with health outcomes . The spatial congruence between people’s reported regular activity locations and the places where they actually undertake activities thus warrants further investigation.