This study links the results of a discrete choice experiment that examines respondents’ behavior in a medical decision to respondents’ answers to a follow-up questionnaire relating to the same experiment.2
The discrete choice experiment we conducted aims to disentangle factors that influence patients’ decision making regarding full knee replacement surgery. We generated a hypo- thetical scenario in which survey participants were presented with three randomly chosen hypothetical persons, the so called vignette persons. All these vignette persons suffer from knee osteoarthritis and have to decide whether they want to pursue full knee replacement surgery or not.
At first, each vignette person described his or her personal history with knee osteoarthritis as well as the treatments that have been tried so far and failed. The vignette person then proceeded to describe his or her personal situation regarding the experienced pain level (high or moderate), the employment status (employed or retired) as well as the opportunity costs that would be encountered if he or she would have the surgery (high or low).
After this description of a vignette’s personal situation, up to three health related factors were presented. First, an orthopedic surgeon assessed the vignette person’s situation and either recommended surgery or stressed the possibility of continuing alternative treatments leaving the decision for or against surgery up to the vignette person. Then additional information parts were presented for random subsamples of vignette persons. These factors were specialist’s second opinions and person specific surgery outcome forecasts. Respondents could then choose whether they want to review a specialist’s second opinion for a specific vignette person and/or whether they want to review the third vignette person’s outcome forecast.3 The specialist’s second opinion was either a strong recommendation that clearly
2This a brief description of the experiment we conducted that focuses mainly on the aspects needed
for this paper’s purpose. For a detailed description of discrete choice experiments in general and our full experimental setup, see chapter 2 of this dissertation.
3At the third vignette person, respondents were also shown one patient testimonial and offered the option to see a second patient testimonial. Since testimonials were at the last choice task and qualitative interviews revealed a minor role of these, the follow up questionnaire focused on the information parts that were shown at every choice task.
identified surgery now as the best option or a statement of substantial reservation against surgery which stressed equal benefits of continuing non-surgical therapies.
The person specific outcome forecasts were introduced in the following way:
[Name] also sought further information on the internet. The homepage of a nonprofit knee osteoarthritis patient aid group offers a tool that predicts likely surgery outcomes. This application uses [Name’s] personal and health informa- tion and compares these with a large sample of full knee replacement surgery patients to predict [Name’s] chances of a successful surgery outcome. The devel- opment of this tool was funded by the U.S. Department of Health and Human Services.
Respondents were then shown a screen that informed them that the vignette person’s chance of a successful surgery outcome was either ”above average” or ”below average”. The chances of success were described in one of three ways: only in verbal terms, in numeric terms including specific percentages, or in a graphic format that used a bar chart to represent the vignette person’s chances of a successful surgery outcome relative to the average chances of a successful surgery outcome.
For each of these vignette persons, the survey participants had to decide whether they would recommend surgery for this person or not and how confident they are this decision. The wording of the decision questions was the following:
1. Do you recommend that Name have full knee replacement surgery now? Yes
No
2. How confident are you of your recommendation?
Please use this scale where 1 means you are not at all confident and 10 means you are absolutely confident.
Not at all Absolutely ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
1 2 3 4 5 6 7 8 9 10
Once the actual DCE was completed, respondents filled out a follow-up questionnaire regard- ing their perceptions of the factors we presented them with. This paper uses the questions that establish which factor respondents considered the most influential in their decisions and which factor they considered to have been most helpful in their decision making process. To find out whether respondents considered the personal situation or one of the health related factors the most influential factor when deciding, the following question was asked:
In general, which of the following most influenced your recommendations for the people considering full knee replacement? (Select only one)
People’s personal situation Physician’s recommendation Second opinion
Probability of successful surgery
The following question was used to elicit whether respondents considered the additional information conveyed in two of the health related factors, the second opinions and the person specific surgery outcome forecasts as most helpful:
Aside from people’s personal situations and the physician’s recommendation, which additional information was most helpful to you for making your recom- mendations? (Select only one)
Second opinion
Probability of successful surgery