One problem with questionnaires is that they ask one thing at a time. Do you prefer a hotel room with a sea view when you are on vacation? You probably answer yes. But do you prefer the sea view even if the room is above the disco, or costs 500 EUR per night? If you only ask one thing at a time, then it is difficult to know how different factors interact, how important they are relative to each other.
One way to get past this limitation is to ask people to choose between two alternatives, where the alternatives have several different attributes.
- Hotel room A: (1) View: sea (2) Price: 200 EUR per night (3) Distance to the center: 30 minutes walk (4) Sound level: high.
- Hotel room B: (1) View: parking (2) Price: 100 EUR per night (3) Distance to the center: 40 minutes bus ride (4) Sound level: low.
Which room do you choose, A or B? The choice tasks are repeated while the attributes are varied systematically. In this way, one can learn more about what people prefer, than through a regular questionnaire. One can see how different attributes interact and which attributes are more important than others are. One can also calculate how much more important an attribute is over another.
The same kind of study can be done about genetic risk information instead of hotel rooms. Jennifer Viberg Johansson at CRB recently did such a study. Four attributes of the risk information were varied in the choice tasks:
- (1) Type of disease (2) Probability of developing disease (3) Preventive opportunities (4) Effectiveness of the preventive measure.
Which of the attributes was most important to the people who participated in the study? How much more important was it?
It turned out that the most important attribute was the effectiveness of the preventive measure. If the information contained an effective preventive measure, the respondents clearly preferred that information. The effectiveness of the preventive measure was twice as important to know, compared to the probability of developing the disease.
Apparently, it is important for people to be able to influence the risk. One conclusion in the study is that when risk information says that there is an effective preventive measure, then risk communication can focus more on the preventive measure than on the probability of developing disease.
The method is called, “Discrete Choice Experiment.” If you want to look more closely at the method and get more results, read Jennifer Viberg Johansson’s article in Genetics in Medicine.
Viberg Johansson, J., Langenskiöld, S., Segerdahl, P., Hansson, M.G., Hösterey Ugander, U., Gummesson, A., Veldwijk, J. Research participants’ preferences for receiving genetic risk information: a discrete choice experiment. Genetics in Medicine, 2019