• What is assessed?
• How is the measurement conducted?
• When is this method used?
• How are estimates of physical activity derived?
• Strengths and limitations
• Populations
• Further considerations
• Resources required
• Instrument library
• Development of new questionnaires
• References

Questionnaires vary greatly in their scope and level of detail and dimensions are not recorded to the same extent by each. The face and content validity of the specific questionnaire should therefore be considered alongside the research question, for example:

1. Is information on domains or other context of activities needed?
2. Is information on types of activities needed?
3. What time frame needs to be covered (e.g. lifetime, past year, past week, past day)?
4. Is quantification of activity to be intensity specific or more comprehensive (e.g. MVPA or total physical activity energy expenditure)?

Questionnaires are limited in their ability to estimate physical activity energy expenditure at individual level and have varying validity for categorising individuals into groups and ranking activity levels. The dimensions of physical activity assessed by questionnaires are described in Table P.2.1.

Table P.2.1 The dimensions which can be assessed by physical activity questionnaire.

Physical activity questionnaires are completed retrospectively. In contrast, a diary or log is completed as physical activity occurs. The respondent typically answers questions about the duration and frequency of physical activity of different types, intensities and/or occurring in different domains or contexts. Questionnaires vary from very brief (1-4 items) to much more detailed (60 items).

The time frame varies from previous day to entire lifetime:

1. Instruments with greater time frame can reduce bias due to season or day of week.
2. Short-term recalls avoid long-term averaging and can provide more detailed information on type and contexts of activities, however replicate (3 to 4) measures are needed to account for variation by season or day of week.

Options regarding use of questionnaires include:

Interviewer vs. self-administered

1. Self-administered (paper-pencil or electronic): favoured in large-population based studies as less resource intensive
2. Interviewer-administered (face-to-face, phone): interviewer facilitates comprehension of questions and recall process. This can increase validity but comes with greater cost (hiring and training of interviewer, efforts to limit inter- and intra-interviewer variation).

Benefits of electronic vs. paper-pencil

1. Greater flexibility e.g. by adding explanatory messages, error corrections and prompts
2. Possibility of branching between questions based on prior answers
3. Immediate data entry, avoiding coding errors and missing data
4. Possibility of direct scoring, reporting and interpreting of results
5. Reduction of research time and cost
6. Potentially greater motivation among participants

Proxy reports

Proxy methods refer to the implementation of questionnaire methods in scenarios where the respondent is not the individual being assessed. The choice of proxy-reporter may be vital to the accuracy of the reports, and normally made on the basis of intimate knowledge of the individual, proximity, or their professional capacity.

Assessing physical activity by questionnaire is a complex task, which may be particularly difficult for some populations, such as: young children, adults with cognitive impairment, chronically ill, disabled. Individuals may lack the cognitive ability to recollect the intensity, frequency and particularly the duration of activities. Alternatively, they may not interpret questionnaire items as intended (especially those with complicated designs), or fully understand the meaning of abstract terms such as “moderate to vigorous physical activity”.

Based on issues of equity, inclusivity, sample size, missing data and bias, use of proxies may be preferable to excluding or not investigating individuals and populations who cannot self-report. Proxy methods also provide some degree of objectivity of estimates of physical activity – individuals do not report their own activity and should have no control over what is recorded.

Use of a proxy-reporter has limitations, such as:

1. Level of observation of the individual’s activity by the proxy-reporter – this is difficult for habitual activity over a number of days, weeks or years, and some domains of activity may be inaccessible.
2. Memorisation and recall of all of the dimensions of physical activity by proxy-reporter is also a complex task
3. Estimation of activity intensity for another individual is particularly difficult, especially when there are differences in age, sex, body mass or degree of disability between subject and proxy-reporter
4. Social desirability bias such as in the case of teachers, parents and care workers, all of whom may have cause to present a more desirable account of the individual’s physical activity
5. Reports may be influenced by the proxy-reporter’s characteristics or subjective experiences of their own physical activity
6. Potential heterogeneity of proxy-reporters (e.g., spouse, trainer, coach, parent, caregiver) within studies
7. It may be difficult to compare proxy-reports from different reporters or with subjective reports

Since questionnaires vary greatly in their scope and level of detail, so does their usage in different types of study. Physical activity questionnaires are the most widely used subjective instrument in large population-based cohorts and surveillance systems.

Brief 1 - 4 item instruments have been used in:

1. Epidemiological research to stratify population into categories of physical activity exposure and compare disease incidence between categories
2. A clinical setting as a screening tool for identification of individuals at increased risk for disease
3. For example: Short EPIC PAQ (InterAct Consortium et al., 2011)

Short 5 - 15 item instruments have been used in:

1. Descriptive epidemiology
2. Assessment of prevalence of major physical activity outcomes
3. Surveillance of adherence to guidelines on moderate-to-vigorous physical activity
4. For example: Short-form IPAQ (Craig et al., 2003), GPAQ (Bull et al., 2009)

Detailed 15 - 60 item instruments have been used to:

1. Quantify patterns of physical activity and physical activity energy expenditure
2. Examine dose-response associations with health outcomes
3. Capture more detailed information about the type, context and intensity of physical activity
4. For example: RPAQ (Besson et al., 2010), Long-form IPAQ (Craig et al., 2003)

The outcome variables produced from questionnaire data vary by method, but can include:

1. Classification of individuals in broad levels of physical activity participation (e.g. inactive, moderately inactive, moderately active, and active)
2. Duration of physical activity occurring at different intensities (e.g. minutes of moderate-to-vigorous physical activity per week)
3. Total physical activity energy expenditure (sometimes expressed as MET-hours per week)
4. Duration of different types and domains of physical activity (e.g. minutes of occupational physical activity per week)

Interpretation of data from a questionnaire is aided by additional information, such as:

1. Demographic data (e.g. age, sex)
2. Anthropometric data (e.g. body mass)
3. Energy cost tables
4. Assumptions about activity levels (e.g. that a manual labourer is more active than an office worker)

It is usual for MET values to be assigned based on the intensity or type data reported by the participant. These MET intensity scores are used alongside the questionnaire reported duration and frequency to derive the volume of activity.

This approach assumes the following:

1. MET values recorded during calibration studies are generalisable to the sample of the current investigation
2. MET values of activities are constant within and between individuals
3. Physical activity intensity is uniform during activities
4. Durations of activity reported represent the actual time for which the activity was conducted, for example, a 1 hour swim session may include changing and showering time

The extraction of features such as MET-hours in different types or domains is an intermediary step, these features can then combined to estimate final target variable(s), or be used in their current state.

Strengths and limitations vary by questionnaire; however, the key characteristics of questionnaire methods are outlined in Table P.2.2.

Table P.2.2 Characteristics of questionnaire methods.>

1. Population determines choice of questionnaire. Different populations report different activity types, contexts and/or patterns, and may require different administration modes, different language, etc.
2. The questionnaire should be examined in terms of reliability and validity in a population similar to the one to be assessed
3. Questionnaires are culturally dependent (activity types, language, etc.)
4. Considerations relating to the use of questionnaires for assessing physical activity are summarised by population in Table P.2.3

Table P.2.3 Physical activity assessment by questionnaire in different populations.

1. The questionnaire should be well formatted and easy to complete
2. Clear instructions (ideally face-to-face) must be provided

1. Questionnaire: paper-pencil or electronic
2. Cover letter, or detailed instructions on the cover for self-administered PAQ
3. Trained interviewers for interviewer-administered PAQ
4. Instructions for completion and return regardless of media
5. For mailed questionnaires a pre-paid stamped address envelope
6. Standard operating procedures for interviewers and coding
7. Data entry, cleaning, and summarising code
8. Compendium of physical activities

A list of specific questionnaire instruments is being developed for this section. In the meantime, please refer to the overall instrument library page by clicking here to open in a new page.

If a new questionnaire is to be developed:

1. Can existing valid questionnaires be adapted and/or combined?
2. Adapt format and layout to population (e.g. larger font and tracking lines for elderly); ensure clarity and structure; give precise instructions; ask questions in precise manner, one piece of information at a time; present questions by domains and use chronologically where possible; use closed questions.
3. Is reference time frame appropriate? Is there likely to be a seasonal effect to physical activity in the population under study?
4. Pilot testing for refinement of questionnaire, which aids with choice and order of activities, response categories, etc.
5. Is choice of criterion optimal when examining validity? Not all criterion measures are equally appropriate as criterion for the different dimensions derived from a questionnaire.
6. Allow for additional socio-demographic questions.
7. Questionnaire must be valid for the population under study, which may be difficult for population groups which are studied less frequently.
8. Modified questionnaires require testing of validity and reliability.

For proxy methods, it is not advisable to simply translate a self-report instrument to proxy-report without testing. A suitable proxy-report method must therefore:

1. Be appropriate for the dimensions, purpose, context and population in the same way a self-report method should.
2. Be valid and reliable when used via a proxy-reporter; this requires careful consideration and testing – methods which are suitable for use in self-report may not be appropriate or feasible by proxy.

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