We recommend including the reference period and the desired averaging method in the question text itself, rather than in the instructions for completing the survey. It might also be advisable to underline the specific mode of transportation being asked about in questions 1–3 (see findings for question 2). For respondents who do not own a car, we recommend including an instruction to clarify that trips as a passenger or in borrowed cars should be included.
Thinking about the past four weeks:
On how many days a week have you made your everyday trips by car (such as commuting to work, shopping, or leisure activities)?
Please include both the routes you drove yourself and the routes that someone else drove.
General Probing, Specific Probing, Category-Selection Probing, Emergent Probing
Information on the purpose and aim of the test:
The question is intended to determine the average number of days per week, over the past four weeks, on which respondents have traveled everyday distances by car. The term “routes” refers to trips from A to B with a specific destination and excludes trips that begin and end at home and are primarily for the purpose of driving around (e.g., drives in a convertible). The word “daily” in the question refers to recurring activities, such as the examples listed in parentheses.
As part of the testing, the focus was on how the test persons went about calculating the weekly average. To this end, researchers examined how they understood the reference period and whether they took it into account. Test persons were asked whether they understood the terms „routes“ and „daily“ in the intended sense, and whether they also included distances traveled in rental cars, carpooling, or taxis.
Findings:
Most participants answered the question quickly and without difficulty. They made use of the entire range of the response scale. One participant wavered between two response categories but was able to quickly decide on one of the options (“That was a little difficult because five to six would have been the perfect number, but I’d say six is close enough.”, TP01). Another participant changed her answer from “1–3 days a week” to “4–5 days a week” during the follow-up questions because she realized that she actually drives more often than she had initially thought (TP11).
How do the participants interpret the reference period, and do they take it into account in their responses?
Six of the twelve participants stated that they had based their answers on the past four weeks (TP01, 04, 05, 06, 08, 12), while the other six had thought more generally about their behavior. However, in almost all cases, the past four weeks represented typical weeks for the participants, which is why they did not (consciously) distinguish between the past four weeks and a typical week. Some participants mentioned that the past four weeks had not included vacation periods or periods without classes.
§ “I was just thinking about things in general—not specifically about the last four weeks.” (TP03)
§ “The last four weeks—that was mentioned in the question. Starting from today, I went back in time. Although it doesn’t make any difference whether it says four weeks or four months.” (TP04)
§ “I was thinking of a week, but it’s always the same thing. I mean, a typical workweek, not a vacation.” (TP07)
§ “The last four weeks—as indicated above—and then the number of days per week.” (TP08)
§ “You can even apply that to the whole year, because the workdays are the same and the activities are, by and large, the same too, so everything is pretty much the same.” (TP10)
§ “Over the past four weeks, but this is the usual routine every week. Sometimes it’s just three days, sometimes six, but usually it’s four to five days.” (TP12)
Only for Test person 02 did the activity patterns over the past four weeks appear to deviate from her normal routine. This test person had spent three of the past four weeks at vocational school rather than at her usual training facility. She read the time specifications in the questionnaire with increased attention and ultimately based her answer on a typical workweek.
“At first, I thought about the last four weeks, and then I read the sentence below it: ‘Please indicate the average number of days in a typical week.’ Then I backtracked a bit and thought about what a more typical week would look like than the last four, and I came up with one to three days a week.” (TP02)
The test person's response makes it clear that, in cases where the last four weeks have been atypical, the instructions for completing the form can be interpreted as a directive to base the response on typical weeks rather than calculating the average of the past four weeks.
Are the terms “routes” and “everyday” understood in the intended sense?
All participants thought about their daily lives and how they travel their regular routes. For example, one participant, who is retired, explained that she primarily considered her shopping routes (“About my daily life. I travel distances between 5 and 15 kilometers to go shopping. I always check where the best deals are, and then I decide where to go,” TP12). Other participants thought about their commutes to work, to school, or to their training center; places where they pursue their hobbies; trips as a “parent taxi”; and regular get-togethers with friends. None of the participants thought about trips where the goal was simply to drive around.
§ “I’d say I go to work twice a week and am in [CITY] at least four to five times. To get there, I drive to the nearest train station every time. Once a week, I go shopping. I also meet up with friends often. I’d say it’s probably five to six times. Then usually one or two more times on the weekend. I just live in a village.” (TP01, Answer: 6–7 days a week)
§ “[I thought about] shopping and work, then I go to my parents’ house, and drive my daughter to her extracurricular activities, physical therapy, and sports. And most of the time, to be honest, I do all of that by car. These are all weekly activities.” (TP07, Answer: 6–7 days a week)
§ “Once a week, I ride along with someone to go shopping together. We also do leisure activities together from time to time, so there might be a second day [a week] as well.” (TP08, Answer: 1–3 days a week)
§ “On my way to work, but also on my way to the swimming pool, where I go regularly […] I sometimes walk to run errands.” (TP09, Answer: 6–7 days a week)
§ “That’s because of my work situation—I drive to work three days a week and maybe use the car one or two days in my free time, for a trip, to go shopping, or to visit people.” (TP10, Answer: 4–5 days a week)
Two participants did not include family visits in their considerations (TP05, 11) because they did not consider them “everyday,” even though they take place regularly:
“I still go visit my father once a week. To do that, I have to drive 80 kilometers south. But that’s always on Saturdays, not on weekdays. Otherwise, it would be six to seven days a week. But sometimes I take the train there, so it’s not a regular thing. Four to five days is more accurate.” (TP11, Answer: 4–5 days a week)
Do the test persons only think about driving their own cars?
Participants who owned their own car generally only thought of trips they took in that car or in cars owned by other household members, or of situations in which they were passengers. When asked about other ways to travel by car, they generally stated that they had not used those options.
“I hadn’t even thought about taking taxis right now, but I don’t really do that. So, [I was thinking] about my own car and my parents’ cars. I also borrow my brother’s car sometimes.” (TP01)
Two participants reported having taken a taxi in the past four weeks (TP02, 05), for example, to attend a concert. Participant 08 explained that she generally uses car-sharing services and also rents cars on an as-needed basis for moves or trips. In all cases, however, the participants explained that these were not regular trips, or that these trips had not taken place in the past four weeks, and that they had therefore not included these trips in their responses.
How do test persons who don't own a car answer this question?
Three participants did not have access to a car of their own or one shared with household members. One of these participants had no trouble at all with the question (TP06). She stated that she did not have a driver’s license and never drove a car—not even as a passenger—but instead traveled everywhere by bicycle or public transportation. The other two participants asked for clarification on how to interpret the question.
§ “That’s the question. I don’t have a driver’s license at all, but I often go shopping with family members. Is that what this is referring to? Does the question mean ‘by car’ in general, or ‘me driving the car’?” (TP03)
§ “It says ‘by car’ here, so it doesn’t have to be my own, does it? Or how am I supposed to understand that? Does that include my girlfriend’s car, too?” (TP08)
One of the participants explained that phrasing such as “in one’s own car” or “in any car” would make the question clearer (TP08). However, even these two participants ultimately decided to include car trips in which they were passengers.
“I’ve been thinking in general about how often I’m in a car. I chose ‘less than once a week’ because I don’t have a car myself, and neither does my partner. So maybe once every two weeks, we go shopping with a family member.” (TP03)
