We reached thematic saturation after interviewing 20 patients. The participants’ mean (SD) age was 64.6 (18); 60% male, 84% were non-Hispanic Whites, 10% Blacks, and 60% had a college education or higher. Participants were recruited from both medical and surgical medical units. Several themes regarding difficulties understanding uncertainty emerged.
Theme 1:Rejection of uncertainty
Some participants rejected uncertainty altogether, and instead focused on the possible mechanisms of action underlying an outcome once it had already occurred. One participant said,
“Well I kinda think there’s a reason for it. I don’t know if I would call it random or chance. There’s a reason why it’s not working.” (Interview #2)
Others stated,
“I mean if you feel like you have the tendency, that’s not random, you know.” (Interview #5)
“It’s ridiculous because it’s not a chance. You either get it or you don’t. You have a predisposition for it and you don’t know it and then you find out when you take it.” (Interview #19)
These participants focused on the reasons why someone would or would not experience a certain risk or a benefit, whether it was an unknown predisposition, an interaction with another medication, allergic reaction, etc. They used terms such as predisposition, tendency, and reason. They did not acknowledge the role that “chance” had in the development of a risk or benefit.
For these participants, neither the icon array nor spinner appeared to facilitate acceptance of uncertainty:
“According to the diagram [icon array], it looks good, but you don’t know until you know.” (Interview #15)
“I don’t like it [the spinner]. Yeah. It’s just a- it’s like a toy… It doesn’t have a brain. This is cardboard, I mean… It can’t predict. It’s not god.” (Interview #6)
“Well there are some people who would get stomach problems. So there’s definitely- there definitely are people. But they’re not talking about those people. They’re talking about me.” (Interview #2)
Theme 2:Failure to distinguish between aleatory and epistemic uncertainty
Several participants interpreted uncertainty as mainly epistemic. These individuals felt that expert knowledge could reduce or eliminate uncertainty and/or that one’s own knowledge from prior experiences could do the same. Illustrative examples include:
“I think with enough information, you could answer in advance whether it would relieve your pain.” (Interview #2)
“I think as much as experts know, they don’t know everything. But you have to trust that they’re gonna know that.” (Interview #2)
“They know something that I don’t know.” (Interview #17)
“Uh, we’re not, um, scientists that we can predict what a pill is gonna do.” (Interview #6)
These individuals and several others strongly felt that experts possessed knowledge that would help them predict whether they would experience a certain risk or benefit. They repeated words such as scientists, predict, and knowledge.
Additionally, many others felt that personal knowledge from prior experiences could reduce uncertainty. For example:
“I would say I would probably not get stomach problems at all, due to the fact that in the past, any medication I have taken, I really have never had a problem with.” (Interview #17)
“The other question is that you know your body and you know how it responds to new things, so you do have that information or knowledge from past experiences.” (Interview #20)
These participants correctly believed that the knowledge they possessed from their own past experiences could decrease uncertainty. If they had had a similar side effect in the past, then they seemed to believe they had a higher chance of experiencing it again and vice versa. However, they tended to overweight this information and to classify their risk as either present or not present.
Theme 3: Difficulty distinguishing between different magnitudes of probabilities
Some participants accurately distinguished between different magnitudes of probabilities while others did not. Of those who were able to differentiate between magnitudes, some did not find the visual aids helpful.
“I like math and I’m good at math and you told me 20 percent. For me, it’s not very helpful [the spinner]. Not that it’s not helpful, it’s just maybe if it was somebody… Like somebody, you know, I guess maybe somebody who’s more of a visual person?” (Interview #9)
“I don’t think it [the spinner] does a whole lot unless you really don’t know percentages or things like that. But they use it for breaking down costs and budgets and all kinds of other things. If I don’t know how much 20 percent is, then I guess I could look at this and have a clue, but so maybe for some people it’ll help but, I don’t find it a big help.” (Interview #16)
Furthermore, among those who did differentiate between magnitudes, some translated the numeric information into ordinal categories:
“You know, I got a good chance of not getting sick. I got a smaller chance of possibly getting sick.” (Interview #7)
“I mean, you know, there’s 80 percent over here and then this little 20 percent.” (Interview #10)
“I would say little [the risk associated].” (Interview #6)
These individuals constructively dealt with probabilistic information by creating mental representations of categories of risk. Others, however, categorized any risk as 50%:
“You got a fifty-fifty chance basically that it’s going to work or it’s not, even though it’s only 20 percent demographic but, you know, there’s that fifty-fifty chance it’s going to take.” (Interview #1)
“I say 50% [chance of medication working].” (Interview #13)
They ignored the numeric probability that was given and deemed any risk as having a 50% chance of occurring.
For one participant, seeing the icon array appeared to hamper, rather than facilitate, understanding of possible outcomes:
“No I guess it would- it could. It’s not totally out of the question. But if you have to base it on, you know, statistics here, um, oh boy. Now I get myself all messed up.” (Interview #2)
Theme 4: Reduction of uncertainty by manipulation of the scenario to eliminate choices
Another major theme that emerged was one in which participants reduced uncertainty by manipulating the scenario to eliminate the need to attend to probabilities at all. In these cases, participants reduced the options available to a single rational choice by revising the severity of symptoms. For example,
“I would say if it’s sort of a life or death situation, then you don’t care as much about the risk.” (Interview #3)
“Well I think if people are really suffering that—and if that’s the only thing available to them then they should do it.” (Interview #12)
“However, being somebody who really suffers from this, I would take the risk and take it anyway because it’s worth it to try.” (Interview #2)
By increasing pain or suffering, these participants eliminated the option of not accepting treatment. Words and phrases such as suffering and life or death were common in these individuals.