Judgment and Decision Making, vol. 1, no. 1, July 2006, pp. 64-75.
Can avoidance of complications lead to biased healthcare decisions?
Jennifer Amsterlaw
Brian
J. Zikmund-Fisher
Angela Fagerlin
Peter A. Ubel1
Abstract
Imagine that you have just received a colon cancer diagnosis
and need to choose between two different surgical treatments.
One surgery, the "complicated surgery," has a lower mortality
rate (16% vs. 20%) but compared to the other surgery, the
"uncomplicated surgery," also carries an additional 1% risk
of each of four serious complications: colostomy, chronic
diarrhea, wound infection, or an intermittent bowel
obstruction. The complicated surgery dominates the
uncomplicated surgery as long as life with complications is
preferred over death.
In our first survey, 51% of a sample (recruited from the
cafeteria of a university medical center) selected the
dominated alternative, the uncomplicated surgery, justifying
this choice by saying that the death risks for the two
surgeries were essentially the same and that the uncomplicated
surgery avoided the risk of complications. In follow-up
surveys, preference for the uncomplicated surgery remained
relatively consistent (39%-51%) despite (a) presenting the
risks in frequencies rather than percents, (b) grouping the 4
complications into a single category, or (c) giving the
uncomplicated surgery a small chance of complications as well.
Even when a pre-decision "focusing exercise" required people
to state directly their preferences between life with each
complication versus death, 49% still chose the uncomplicated
surgery.
People's fear of complications leads them to ignore important
differences between treatments. This tendency appears
remarkably resistant to debiasing approaches and likely leads
patients to make healthcare decisions that are inconsistent
with their own preferences.
Keywords: risk communication, medical decisions, cognitive biases
1 Introduction
Over the past several decades, there has been a revolution in
healthcare decision making, with much more recognition among
healthcare practitioners that patients deserve a role in their
healthcare decisions. A few decades ago, oncologists frequently
withheld cancer diagnoses from patients out of fear that patients
could not handle this information (Novack et al., 1979). It was
not uncommon around this time for a woman to wake up from a
breast biopsy procedure to learn not only that she had breast
cancer, but that the surgeon had already taken the liberty of
performing a mastectomy (Lerner, 2001). These practices are
unheard of today. Patients with cancer diagnoses are
told about their diagnoses and are often involved in important
treatment decisions: deciding for example, whether to opt for
surgical therapies versus radiation. Healthcare practitioners
are involving patients in these decisions out of recognition that
many of these decisions are not purely medical judgments but also
include value judgments that only patients themselves can
make (Gafni & Whelan, 1998). It is the patient who
needs to consider tradeoffs between the benefits of treatment and
the potential complications treatments entail. The "right
choice" for any specific patient therefore often depends on that
patient's preferences or attitudes about possible outcomes.
At the same time as the medical community has been moving toward greater
patient involvement in healthcare decisions, decision-making research
has identified a host of circumstances in which people don't seem to
make the right choice. For example, people make different choices when
their options are framed as gains or losses, preferring a surgical
procedure with a 90% survival rate to one with a 10% mortality rate,
even though the two procedures are identical (McNeil, Pauker, &
Tversky, 1988). They prefer different healthcare providers when
evaluating each possible doctor separately versus when considering the
set of possible physicians all at once (Zikmund-Fisher, Fagerlin, &
Ubel, 2004). Their choices are unduly influenced by uninformative
anecdotes (Ubel, Jepson, & Baron, 2001). A recurrent theme in this
line of research is that people's preferences are often inconsistent or
easily overridden by subtle cognitive processes (Fischhoff, 1991).
On one side, then, is a push to give patients more information so they
can make decisions that are consistent with their personal preferences,
while on the other side is a growing psychological literature revealing
people's tendency to make choices that are in fact inconsistent
with their own preferences (Ubel, 2002). These two worlds are in the
process of colliding, as clinicians and researchers become aware of the
likelihood that patients, even when given comprehensible information
about important healthcare tradeoffs, will make irrational or
inconsistent choices because of the way they process the information
they are given.
Take, for example, a common rule of thumb about the kind of
information healthcare providers are expected to give patients
before enrolling them in research trials or before consenting
them for invasive surgical procedures. Clinicians are expected
to inform patients about any treatment complication that is
reasonably likely to occur. Although there is no absolute cutoff
for how likely a complication must be for clinicians to tell
patients about it, most experts feel that clinicians should tell
patients about any moderately severe complication that occurs at
least 1% of the time, and should inform them about serious
complications that occur even less often than that. This
approach to risk communication is reflected in the Food and Drug
Administration's Guidance for Industry regarding the content and
format of prescription drug labels ("Guidance for industry:
adverse reactions section of labeling for human prescription drug
and biological products - content and format," 2006).
Many clinicians recognize the potential problems created by this rule of
thumb. A long list of potential complications may scare patients away
from what otherwise appears to be their best treatment option. Imagine
a patient with colon cancer who faces a choice between the following
two hypothetical surgical procedures: one surgery (the "complicated
surgery") cures 80% of patients without complications, cures 4% of
patients with one of four complications (leaving them with either
chronic diarrhea, a slow healing wound infection, an intermittent bowel
obstruction, or a colostomy), and is unable to cure 16% of patients,
who therefore die of the cancer. Another surgery (the "uncomplicated
surgery") cures 80% of patients without complications and is unable
to cure 20% of patients, who therefore die of the cancer. In a pilot
study, we determined that the vast majority of people believe that
living with each of the four surgical complications is better than
being dead. For those people, the complicated surgery is the choice
that best fits these preferences. Yet the sheer number and graphicness
of these four complications might nevertheless be enough to compel
these people to choose the uncomplicated surgery.
Our current research has two goals. In Study 1, we tested how people
respond in a decision-making situation where their `best' treatment
option carries a risk of several unpleasant complications. Using the
colon cancer case just described, we asked people which treatment they
would choose. We found that many people prefer the uncomplicated
surgery - that is, they opt for the treatment with a higher risk of
death just to avoid the possibility of complications. In Studies 2
through 4, we varied how we presented the scenario information to
investigate the stability of this choice and to investigate underlying
processes. Our results confirmed that for most people, choice of the
uncomplicated surgery was actually inconsistent with their stated
preferences and values. Nevertheless, even when we made people's own
preferences transparent, many continued to make inconsistent choices.
We conclude that avoidance of treatments carrying small risks of
unpleasant complications leads to inconsistencies between stated
preferences and people's decisions, and that these inconsistencies are
pervasive and difficult to eliminate.
2 Study 1
In Study 1, we presented participants with the colon cancer scenario
described above (see Appendix for full text). Accompanying the scenario
was a simple table summarizing the treatments (Table 1).
Table 1: Treatment summary table presented with scenario in Study
1.
| | Surgery 1 | Surgery 2 |
| Possible outcome | (complicated) | (uncomplicated) |
|
Cure without complication | 80% | 80% |
| Cure with colostomy | 1% | |
| Cure with chronic diarrhea | 1% | |
| Cure with intermittent bowel obstruction | 1% | |
| Cure with wound infection | 1% | |
| No cure (death) | 16% | 20% |
|
|
It should be noted: in none of our studies did we refer to the treatment
options as "the complicated surgery" or "the uncomplicated
surgery," but instead referred to them throughout as Surgery 1 and
Surgery 2. However, for purposes of presentation, we will refer to
them throughout this manuscript as the complicated and the
uncomplicated surgery.
The choice set up a tradeoff between mortality risk and risk of serious
surgical complications: the complicated surgery had a lower mortality
rate (16% vs. 20%) but by the same margin of difference carried an
additional 1% risk of each of four complications: colostomy, chronic
diarrhea, wound infection, or intermittent bowel obstruction. (Note
that the scenario did not explicitly describe the outcomes as mutually
exclusive, and in this respect the information is consistent with how
side effects and complications often occur.) In pilot testing, we
determined that the vast majority of people (90%)
thought that each of the four surgical complications was preferable to
dying of colon cancer. Thus, for most people, the complicated surgery
should be preferred to the uncomplicated surgery. However, we expected
that the desire to avoid the complications associated with the
complicated surgery might lead some of these people to prefer the
uncomplicated surgery.
2.1 Methods
2.1.1 Participants
Participants were volunteers recruited from a university office building
and the cafeteria of a university medical center. A total of 87
participants completed the questionnaire. The sample was 91%
Caucasian and 65% female. The mean age of participants was 39.2 years
(SD = 12.9) and 43% of participants had completed at least a college
degree.
Participants received the scenario as part of a written questionnaire
that also contained other questions about unrelated medical
decision-making topics. Demographic questions about participants' age,
race, education, profession, and personal experience with colon cancer
were also included. Participants completed the questionnaire at their
own pace.
2.2 Results
Out of 87 participants, 44 (about 51%) selected the
uncomplicated surgery, the dominated alternative. Analyses
showed no significant effects of gender, race, or education level
on surgery choice. 42% of our sample reported being affiliated
with the medical/health profession; these individuals did not
make significantly different surgery choices (39% vs. 58%,
c2(1) = 3.06, n.s.). There were also no differences as a
function of prior experience with colon cancer. While 44% of
participants reported that they or a close friend or family
member had had colon cancer, these individuals chose the
uncomplicated surgery at the same rate as other participants
(54% vs. 48%, c2(1) = .315, n.s.). Respondents who
choose the uncomplicated surgery tended to be older than
respondents who chose the complicated surgery (M age = 43.3
vs. 35.1 years, t(84) = 3.10, p < .01).
Most participants (87%) provided a written explanation for their
surgery choice. Of these, 94% of participants selecting the
uncomplicated surgery cited a desire to avoid complications as the
reason for their choice, with 60% simply reporting that they did not
want complications and 34% also explicitly mentioning the tradeoff
with mortality risk. Two additional people mistakenly believed the
uncomplicated surgery improved their chances of survival. In contrast,
100% of participants selecting the complicated surgery cited its
higher survival rate as the reason for their choice, with 68% simply
mentioning its better survival rate and 32% also describing the
tradeoff between death and complications.
2.3 Discussion
Table 2: Treatment summary table presented with Study 2 "Complications
Added" version.
| | Surgery 1 | Surgery 2 |
| Possible outcome | (complicated) | (uncomplicated) |
|
Cure without complication | 80% | 80% |
| Cure with colostomy | 1% | 0.25% |
| Cure with chronic diarrhea | 1% | 0.25% |
| Cure with intermittent bowel obstruction | 1% | 0.25% |
| Cure with wound infection | 1% | 0.25% |
| No cure (death) | 16% | 19% |
|
|
Results from Study 1 showed that regardless of background factors such
as gender, race, education, medical affiliation, or previous experience
with colon cancer, many people preferred the uncomplicated surgery to
the complicated surgery. Written responses indicated that this
preference stemmed from a desire to avoid complications. Most
participants appeared to have understood the information presented,
with well over half the sample explicitly acknowledging the tradeoff
between mortality risk and risk of complications. However, those who
chose the uncomplicated surgery were unwilling to risk the possibility
of serious complications to improve their overall chance of survival.
Why would this be the case? Barring the possibility that people
actually would prefer to die than live with complications (a
possibility we examine in Study 4), selecting the treatment with the
higher mortality risk seems irrational. We next explored reasons for
this apparent inconsistency.
3 Study 2
Study 2 investigated the possibility that choice was affected by the
number of possible outcomes listed for each treatment option. One
possibility was that people were attracted to the uncomplicated surgery
because it had only two outcomes associated with it - total cure and
death - while the complicated surgery had six possible outcomes, four
of which were ambiguous "cured with complications" outcomes. People
may simply have been averse to this kind of uncertainty, leading them
to choose the surgery with fewer and less ambiguous possible outcomes.
People are notoriously averse to uncertainty. For example, in the
1980s, back when HIV infection was a death sentence, studies showed
that men were happier after they received HIV test results than while
they were waiting for the results no matter what their test
results revealed! The uncertainty of not knowing their HIV status was
harder to cope with than the certainty of a rapid demise (Sieff, Dawes,
& Loewenstein, 1999). The same phenomenon was
demonstrated among people undergoing genetic testing for Huntington's
Disease, a devastating, hereditary neurologic illness that causes
uncontrolled spasms, dementia and death (Wiggins et al., 1992).
Rationally speaking, it should be easier to live with a 50% chance of
Huntington's Disease than a 100% chance. But it is difficult for
people to cope with the uncertainty of a 50% chance of illness.
Uncertainty is so stressful that it can create paradoxical situations.
For example, during World War II, people living in London were deluged
by nightly bombing raids, while those living in the suburbs were raided
sporadically. Objectively speaking, it should feel worse to be bombed
nightly than to be bombed less often. However, people in the suburbs
were significantly more likely to develop stomach ulcers than
city dwellers, because they were so stressed out by the uncertainty of
when they would be exposed to bombing raids (Frederick & Loewenstein,
1999).
Table 3: Treatment summary table presented with Study 2 "Grouped
Complications" version.
| | Surgery 1 | Surgery 2 |
| Possible outcome | (complicated) | (uncomplicated) |
|
Cured without complications | 80% | 80% |
| Cured, but with one of the following complications: colostomy, chronic
diarrhea, intermittent bowel obstruction, or wound infection | 4% | |
| No cure (death) | 16% | 20% |
|
|
We hypothesized that the uncomplicated surgery, despite having a higher
death rate than the complicated surgery, would feel less uncertain to
subjects, and therefore more desirable. To test this, we developed a
new version of the scenario in which the uncomplicated surgery was now
described as carrying a small risk of complications (Table 2). In this
"Complications Added" version, the uncomplicated surgery now carried
a 0.25% risk of each of the four complications described for the
complicated surgery. To compensate for this change while preserving
the same basic probability information, we reduced the death rate for
the uncomplicated surgery from 20% to 19%. If people simply
preferred the uncomplicated surgery because it had less ambiguous
outcomes, they should now prefer it less (even though the decrease in
the death rate actually makes this option more attractive). With both
treatments now carrying the potential for the same set of unpleasant
outcomes, people should be more inclined to choose the option that
maximizes their survival.
The "Complications Added" version also tests an explanation for
choosing the uncomplicated surgery grounded in the non-linear
probability weighting function of Kahneman and Tversky's Prospect
Theory (Kahneman & Tversky, 1979). Prospect Theory holds that very
small probability events are overweighted in decisions. As a result,
the change in the probability of a complication (e.g., colostomy) from
0% to 1% may influence choice far more than the equivalent 1%
reduction in the death rate from 20% to 19%. However, the very small
(0.25%) risks of each complication added to the uncomplicated surgery
in the "Complications Added" version should be similarly
overweighted, and thus Prospect Theory would predict that people should
shift their preferences towards the survival maximizing outcome, the
complicated surgery, when compared to the results from Study 1.
Another possible source of the inconsistency was that people were
relying on a simple tallying strategy to decide on the best option, for
example by counting up the treatments' "wins" and "losses" in each
outcome category. In that case, the complicated surgery may have
looked like a bad option because it had five "losses" to the
uncomplicated surgery (for each of the four complications outcomes and
the death outcome) and only one "win" (for death rate). One
potential way to increase preference for the complicated surgery, then,
would be to reduce its "losses" to the uncomplicated surgery by
presenting the complications outcomes as a single outcome with a 4%
risk, rather than as four separate outcomes each with a 1% risk. This
is what we did in the "Grouped Complications" version of the scenario
(Table 3). We predicted that if a tallying strategy was in use, this
change would increase preference for the complicated surgery.
3.1 Methods
3.1.1 Participants
Participants were volunteers recruited from the cafeteria of a
university medical center, two university office buildings, and a local
shopping center. A total of 80 participants completed the
Complications Added version, and 100 participants completed the Grouped
Complications version. The sample was 84% Caucasian and 57% female.
The mean age of participants was 40.6 years (SD = 16.3), and 47% of
participants had completed a college degree.
The procedure was identical to that used in Study 1. The only
difference was that the probability information was changed, as
described above.
In the Complications Added version, 41 out of 80 participants
(about 51%) selected the uncomplicated surgery, an identical
result when compared to Study 1, c2(1) = 0.01, N=167,
n.s.). In the Grouped Complications version, 40 out of 100
participants (40%) selected the uncomplicated surgery, which
also did not differ significantly from the proportion obtained
with the original scenario, c2(1) = 2.10, N=187, n.s.)
Thus, preference for the uncomplicated surgery did not depend
simply on the number of outcomes possible for each treatment or
on whether the complications were presented as four separate
outcomes or as one.
Participants' explanations for their choice of the uncomplicated surgery
again reflected a desire to avoid complications. Across both versions,
about 80% of participants provided explanations for their choice. Of
these, 23 out of 32 participants (72%) who selected the uncomplicated
surgery in the Complications Added version said they wanted to avoid
complications. Two mistakenly reported that the survival rate was
better for the uncomplicated surgery, while seven (22%) gave a
non-specific explanation, such as "so I'll have a better chance." In
the Grouped Complications version, 26 out of 30 (87%) explained their
choice of the uncomplicated surgery by saying they wanted to avoid
complications. Three gave non-specific "better chance" explanations
and one gave an ambiguous response.
Upon closer examination, three main types of explanations that expressed
a desire to avoid complications emerged. Some people simply said they
wished to avoid complications; some referred to a tradeoff, saying that
they realized that the uncomplicated surgery's death rate was higher
but were willing to take that risk to be free of complications; and
some in effect bypassed the tradeoff by stating that the difference
between the surgeries' mortality rates was too small to be meaningful.
Across both versions of the scenario, responses of these types
constituted 24%, 21%, and 16% of all explanations for choice of the
uncomplicated surgery, respectively.
3.2 Discussion
Table 4: Treatment summary table presented with Study 3 "Reframing"
version.
| | Surgery 1 | Surgery 2 |
| Possible outcome | (complicated) | (uncomplicated) |
|
Cured of colon cancer | 840 | 800 |
| 800 cured without complications | 800 cured without
complications |
| 40 cured with one of the following
complications:
* colostomy
* chronic diarrhea
* intermittent bowel obstruction
* wound infection
| 0 cured with one of the following
complications:
* colostomy
* chronic diarrhea
* intermittent bowel obstruction
* wound infection |
| No cure (death)
| 160 | 200 |
Even when significant changes in the scenario were made, a significant
minority of people maintained preference for the uncomplicated surgery.
This leads us reject to two plausible hypotheses about the predominant
source of the bias. In general, people did not avoid the complicated
surgery simply because of the uncertainty associated with its multiple
and ambiguous options, nor were they relying on a simple tallying
strategy that was overwhelmed by these multiple possible side effects.
Written explanations for choosing the uncomplicated surgery again
indicated strong aversion to complications. A closer analysis of these
explanations yielded two discernable subtypes of responses: A small
number of people appeared to prefer death rather than risk life with
complications, and a larger number believed the difference in mortality
rates was too small to be significant, leaving complication rate as the
deciding factor.
Table 5: Treatment summary table presented with Study 3 "Explicit
Tradeoff" version.
| | Surgery 1 | Surgery 2 |
| Possible outcome | (complicated) | (uncomplicated) |
|
Cured without complications | 800 | 800 |
| Cured, but with one of the following complications: colostomy, chronic
diarrhea, intermittent bowel obstruction, or wound infection | 40 | 0 |
| No cure, death from scar tissue inflammation within 2 years | 0 | 40 |
| No cure, death from colon cancer within 2 years | 160 | 160 |
People's tendency to equate the 16% and 20% the mortality risks is
problematic. Why should people view a 4% difference in complications
rates as significant, but dismiss an equally-sized difference in death
rates? The asymmetry is perhaps most obvious in the Complications
Added case, where both surgeries have the same set of possible
outcomes. In that case, people appeared to view a 3% difference in
the total complications rate as significant, but not a 3% difference
in death rate, even though both surgery options included small
risks of complications. The finding is consistent with prior research
in psychology (Baron, 1997; Fetherstonhaugh, Slovic, Jonhnson, &
Friedrich, 1997; Jenni & Loewenstein, 1997) and medicine (Bobbio,
Demichelis, & Giustetto, 1994; Forrow, Taylor, & Arnold, 1992;
Malenka, Baron, Johansen, Wahrenberger, & Ross, 1993) showing that
people often think about risks in relative, rather than absolute terms.
Specifically, equal sized changes in risk may be perceived as greater
when they represent a larger fraction of the baseline risk level. In
our scenario, people may have focused on the 1% to 4% increase in
complications risk from the uncomplicated surgery to the complicated
surgery because it represents a greater (relative) change in risk than
the 19% to 16% decrease in mortality. Again, this underlines the
point that the risk of unpleasant complications - even when small -
looms inordinately large in people's decision-making in a way not
captured by linear probability weighting.
4 Study 3
When people ignore important probability differences in mortality risk
across options, they effectively bypass the tradeoff that is inherent
in the choice. When the cure rates and death rates are both seen as
equivalent across surgeries, only complication rates remain to
distinguish between the two treatments, and the uncomplicated surgery
is a clear winner. The goal of Study 3 was to explore ways of
heightening people's sensitivity to meaningful probability differences
across options and to the necessary tradeoff between mortality risk and
risk of complications. We created two new versions of the scenario
with this in mind.
In the first of these, the "Explicit Tradeoff" version (Table 4), we
made two major changes. First, we presented the outcome information in
terms of frequencies rather than percents. To emphasize the additional
4% of people whose lives could potentially be saved by the complicated
surgery, we chose to present the information in terms of the likely
outcomes for 1000 people undergoing each treatment. If participants
could see that 40 additional people would be saved by the complicated
surgery, this might reduce their tendency to dismiss the mortality
rates as equivalent. Second, we divided the death outcome for the
uncomplicated surgery into two separate outcomes - death from colon
cancer (the same as in all previous scenarios) and death from "scar
tissue inflammation," a new fatal complication of the uncomplicated
surgery. The probability of death from scar tissue inflammation under
the uncomplicated surgery (4%) was precisely equal to the probability
of being cured with complications under the complicated surgery. With
this change, we hoped people would now more clearly see the tradeoff
they had to make - either incur the risk of surviving with
complications or incur the risk of dying from one.
In the second version, the "Reframing" version (Table 5), we again
presented outcome information in terms of frequencies rather than
percents. In addition, we changed how the information about
complications outcomes was presented. In previous versions, we had
always presented "cured with complications" as an outcome distinct
from being cured without complications. In the Reframing version, we
now presented it as a subset of the larger group of people cured of
their colon cancer, thereby giving that outcome a more positive spin.
We hypothesized that this approach would increase preference for the
complicated surgery by making the complications outcomes seem less
negative and also by highlighting its higher cure rate.
4.1 Methods
4.1.1 Participants
Participants were recruited from the cafeteria of a university medical
center, a local bus station, and the local public library. A total of
76 participants completed the Explicit Tradeoff version of the
questionnaire, and 88 completed the Reframing version. The sample was
67% Caucasian and 54% female. The mean age was 35.3 years (SD = 15.0), and 52% had completed a college degree.
The procedure was identical to earlier versions. Probability
information in the scenario was changed as described above.
4.2 Results
For the Explicit Tradeoff version, 31 out of 78 participants
(40%) chose the uncomplicated surgery. This difference was not
significant when compared to results of Study 1, c2(1) = 1.95, N=165, n.s.). For the Reframing version, 34 out of 88
participants (39%) chose the uncomplicated surgery, again not
significantly different from the original scenario, c2(1) = 2.52, N=175, n.s.).
4.3 Discussion
Although participants in both versions used in Study 3 tended to pick
the uncomplicated surgery slightly less often than in the Study 1 base
case, in neither version did we observe a significant difference in
behavior. Neither making the tradeoff between the risks of death and
life with complications explicit, nor reframing life with complications
as a subset of the cured population, was effective in encouraging
substantially more study participants to select the option that
maximized survival. Of note: in determining the sample sizes for our
studies, we set out to find large differences between versions, looking
for phenomena that explained all or most of the bias. Since our
manipulations of both the risk statistics and the format of their
presentation yielded no dramatic behavior changes, we next considered
the possibility that the observed selection of the uncomplicated
surgery was actually a true reflection of people's preferences between
life with complications and death.
5 Study 4
Selecting the surgery with the higher mortality risk just to
avoid possible side effects seems irrational. But is it? The
18 Century philosopher, David Hume, said,
"It is not contrary to reason to prefer the destruction of the
whole world to the scratching of my little finger." That is,
the rationality of a given choice depends on whether that choice
is consistent with one's goals and values. The uncomplicated
surgery is a bad choice only if people would prefer to live with
complications rather than die. If people actually would rather
die than live with any of the complications, we cannot call them
irrational for choosing the uncomplicated surgery. On the other
hand, if a person thinks that living with complications is better
than being dead, then he should prefer the complicated surgery.
If such a person nevertheless chooses the uncomplicated surgery,
he has made an irrational choice - a choice inconsistent with
his own preferences. In Study 4, we investigated whether
preference for the uncomplicated surgery is in fact an irrational
choice, or whether it simply reflects people's underlying beliefs
about the value of life with complications relative to death. We
did so by having each subject complete a rating exercise in which
they directly compared life with each of the four possible
complications versus death.
A second goal of Study 4 was to examine whether having participants make
such ratings would affect their surgery choices. Thus we compared the
surgery choices of people who performed the rating exercise before
versus after making their surgery choice. If people are choosing the
uncomplicated surgery because they prefer death over life with
complications, then undertaking the rating exercise before making a
choice should not influence people's decisions. However, if
participants do prefer to live with complications rather than die -
but nonetheless make treatment choices inconsistent with these
preferences - expressing a preference for life in a pre-decision
rating exercise could focus their decision-making around those
priorities, leading to greater preference for the complicated surgery.
5.1 Methods
5.1.1 Participants
Participants were recruited from the cafeteria of a university medical
center. A total of 154 participants completed the questionnaire, with
half receiving the "Rate-Before-Choice" version of the questionnaire
and half receiving the "Rate-After-Choice" version. The sample was
89% Caucasian and 62% female. The mean age of participants was 42.2
years (SD = 16.5), and 52% of participants had completed a college
degree. Participants' demographic characteristics (gender, race, age,
education level) did not differ across the two versions of the
questionnaire.
Participants were presented with the same basic scenario used in Study
1. In addition, either before or after their choice, participants
received the rating exercise. This consisted of four questions that
asked "What would be better, being dead or living with ___ ?" for
each of the possible complications: colostomy, chronic diarrhea,
intermittent bowel obstruction, and wound infection. Participants
could respond by selecting either "death would be better" or "living
with ___ would be better." Descriptions of the four complications
(identical to the descriptions provided in the original scenario)
accompanied the rating exercise. In addition, in the Rate-After-Choice
condition, the last page of the questionnaire gave participants the
opportunity to change their original treatment choice if they desired.
5.2 Results
Participants' responses on the rating exercise revealed an overwhelming
preference for life with complications over death. Looking just at the
ratings of participants in the Rate-Before-Choice condition, 71 out of
77 participants (92%) indicated that life with complications was
preferable to death for all four complications listed. On the opposite
extreme, only one participant indicated a preference for death in all
four cases. Five participants (7%) preferred death over life with
complications in some cases but not others, with three people reporting
that they would rather die than live with a colostomy bag and two
reporting that they would rather die than live with intermittent bowel
obstruction. Preference for life with complications was somewhat lower
in the Rate-After-Choice condition, suggesting that the choice activity
affected participants' rating responses. However, 61% of participants
in the Rate-After-Choice condition still indicated that life with
complications was preferable to death for all four complications
listed. Roughly 7% believed death was preferable in all four cases,
with the remaining 32% reporting a preference for complications over
death only in some cases.
In many cases, participants' surgery choices were not consistent with
these preferences. In the Rate-Before-Choice condition (in which 92%
of participants indicated that they preferred life with complications
over death in all cases), 49% of participants went on to select the
uncomplicated surgery, thus selecting a surgery which did not reflect
their stated beliefs. In the Rate-After-Choice condition, 45% selected
the uncomplicated surgery even though 60% then indicated that they
preferred complications over death in all cases. Stated another way,
49% of people who chose the uncomplicated surgery in the
Rate-Before-Choice and 32% of people who chose the uncomplicated
surgery in the Rate-After-Choice condition made choices
inconsistent with their stated preferences. Further, when
participants were given the chance to change their initial choice in
the Rate-After-Choice condition, few did so. Only three switched from
the uncomplicated surgery to the complicated surgery, and four actually
switched in the opposite direction.
Thus, when people were asked directly about whether they thought it was
better to be dead or to live with complications, most said that they
would rather live with complications than die. However, these
preferences were frequently not reflected in their surgery choices.
5.3 Discussion
These results demonstrate that many people who chose the uncomplicated
surgery chose it despite a clear preference for life with
complications over death. That is, their choices contradict their own
preferences. The results from the Rate-Before-Choice condition are
especially striking: People's choices were inconsistent with their
preferences even though they had expressed those preferences only
minutes before.
6 General Discussion
Table 6: Participants' surgery choices across all scenario versions.
Statistics compare proportions against those from Study 1.
| | | Percent selecting | | |
| N | dominated alternative | χ2 | p |
|
Study 1 | | | | |
| Original scenario | 87 | 51% | | |
|
Study 2 | | | | |
| Complications added to uncomplicated surgery | 80 | 51% | 0.01 | .931 |
| Grouped complications for complicated surgery | 100 | 40% | 2.10 | .147 |
|
Study 3 | | | | |
| Explicit tradeoff | 78 | 40% | 1.95 | .163 |
| Reframing | 88 | 39% | 2.52 | .112 |
|
Study 4 | | | | |
| Focusing rating before choice | 77 | 49% | 0.00 | .992 |
|
|
The goal of informed consent discussions in healthcare practice is to
help patients decide which alternatives best fit their individual
preferences. A choice between two surgical operations may hinge, for
example, on how particular patients weigh the relevant risks and
benefits of the two procedures. The same kind of weighing, of pros and
cons, helps people make all kinds of healthcare decisions, such as
whether to enter clinical trials, or whether to undergo risky
treatments for serious illnesses. And because people's attitudes
toward risks and benefits differ, the right choice for any one person
will depend on his/her values. Consequently, experts contend that
patients deserve to receive comprehensible medical information and the
freedom to choose among available alternatives.
Our study reveals one problem with the way informed consent is currently
obtained. As our study shows, when people receive comprehensible
information about their treatment alternatives, they do not always make
choices that fit their own preferences. This in itself is not a new
finding, as people have been shown to be susceptible to a whole host of
biases when making healthcare decisions (Redelmeier, Rozin, &
Kahneman, 1993). However, our study is significant for two important
reasons. First, we have demonstrated a decision-making inconsistency
that is particularly relevant to healthcare decisions: lists of
graphic complications can drive people away from treatments, even when
the same people acknowledge that these treatments are preferable to
other alternatives in terms of expected outcomes. Second, we have
shown just how persistent this inconsistency can be. Even when
people's preferences are completely transparent - even after people
have seen the inconsistencies of their own views - people still make
choices that don't map onto their own preferences. It is as if many of
our subjects told us "the complicated surgery is better than the
uncomplicated surgery, but I prefer to receive the uncomplicated
surgery."
Although none of our manipulations significantly reduced the percentage
of participants selecting the uncomplicated surgery from that observed
in the base case, the three versions yielding the lowest preference for
the uncomplicated surgery rates (Study 2: "Grouped Complications" and
the two versions of Study 3 - see Table 6) all grouped the risk of the four possible
complications into a single category. This suggests that some fraction
of people choosing the uncomplicated surgery were influenced by the
sheer number of categories under consideration. Still, we note that
our studies were powered to detect relatively large effects - that is,
relatively "common" patterns of choice - and in none of these
versions did the percentage of people picking the uncomplicated surgery
ever drop below 39% of the sample, so the impact of this issue is
moderate at best. Most likely, a variety of factors contribute to
inconsistent decision-making in these cases. We hope to clarify these
further in our future research, by conducting larger studies with the
power to reveal subtle processes contributing to - if not completely
explaining - the effect, and by conducting studies that explicitly
assess the role of affect in people's decisions.
Nevertheless, it is worth speculating about potential causes of this
bias. Our initial intuition was that the sheer number of complications
of the complicated surgery was the source of the bias. However, in the
"Complications Added" survey from Study 2, both of the surgical
alternatives have the same number of complications, yet 51% of people
still chose the dominated alternative. This sub-study proves that it
is not simply the number of complications that leads to the bias.
We also predicted that the number of complications, and the graphic way
each complication was described, might make it difficult for people to
perceive the dominance relationship. Perhaps people were just unaware
that one surgery dominates the other. We no longer believe this
explanation, however. To begin with, neither education nor measures of
people's mathematical ability were significantly associated with
treatment choice in any of our studies. Moreover, we presented this
scenario to a random sample of 119 primary care physicians in the U.S.,
and asked them what they would choose for themselves. Almost 40%
chose the uncomplicated surgery, suggesting that neither medical
training nor relevant decision experiences prevent biased choices.
Finally, in Study 4, we asked people to state whether they preferred
death or any of the four surgical complications prior to asking them to
choose between the two surgical alternatives. We believe that this
method should have clarified the dominance relationship, and yet many
study participants were still willing to choose the dominated
alternative.
We are now in the process of exploring other mechanisms that could
explain the source of the bias we have demonstrated in this paper.
One possibility is that the bias results from processes similar to
those documented in studies of betrayal aversion. Research
shows that people are bothered by bad outcomes when the cause of those
outcomes is perceived as some kind of betrayal. For example, people
believe it is worse to be killed in an auto accident by a faulty airbag
than by other malfunctions in a car, because the airbag is supposed to
protect people from injury. (Koehler & Gershoff, 2003) Medical
interventions are supposed to improve people's health, and so the fact
that the complicated surgery might cause other (lesser) harms might be
perceived as kind of betrayal, resulting in aversion to that choice.
Similar tendencies may contribute to well-known omission biases. For
example, people are reluctant to get vaccinated if the vaccine carries
a risk of health side effects, even if the risk/benefit profile of the
vaccine is better than the risk/benefit profile of remaining
unvaccinated (Ritov & Baron, 1990).
The bias may also result from the affective salience of the surgical
complications. Intermittent diarrhea may not have much impact on
people's quality of life, and may not come close to being perceived as
being as bad a death. But diarrhea is icky. So is the thought of a
colostomy or a wound infection. People are much more sensitive to the
probability of emotionally mundane events than to more emotionally
salient events, when making decisions (Rottenstreich & Hsee, 2001). As
a result, because the complicated surgery includes a risk of four
affectively loaded complications, people may feel strong aversion to
that surgery despite the low probability of each complication, and
despite the fact the complications are preferable to the alternative of
being dead. By contrast, our simple description of the risk of death
may lack the emotional salience of the graphically described
complications. Indeed, a number of decision making theories postulate
that anticipatory emotions play a large role in people's decisions, and
can skew the relationship between probability, utility, and
decisions (Damasio, 1994; Finucane, Alhakami, Slovic, & Johnson, 2000;
Loewenstein, Weber, Hsee, & Welch, 2001). Along these lines, people
may know that the complicated surgery is better than the
uncomplicated surgery, but it might feel like the
uncomplicated surgery is a better option. We plan a series of follow
up studies, in which we will try to influence the emotional salience of
the four surgical complications, as well as the emotional salience of
death, to see how that influences people's choices.
Is consistency something people should strive for when making important
decisions? We think so. Consistency is hardly the hobgoblin it is
often made out to be. When confronted with inconsistencies, most
people, in most circumstances, do not merely shrug off the
inconsistency. They try to understand why they have made an
inconsistent choice, or discover some consistency lying underneath the
surface of their choice. The huge field of research on cognitive
dissonance is a testament to the importance people place on achieving
some type of internal consistency in their lives. Of course,
consistency is not always desirable, nor is inconsistency always
troubling. People change their minds over time, for example, and such
inconsistencies, if they can be even called that, can be a sign of
growth or open-mindedness.
Yet in this article we are not exploring reasonable inconsistencies
occurring over the course of people's lives. Instead, across the span
of two minutes, after earlier stating a preference for the
complications over death, many people had no problem choosing the
uncomplicated surgery over the complicated surgery. This is a dilemma.
If the complicated surgery is better than the uncomplicated surgery,
then people should choose it, and if it is not, then their preferences
should reflect this view. We have shown that even when people receive
easily comprehensible information, and when their own preferences are
made clear to them, they often still make choices that don't fit their
own preferences.
A couple decades ago, medical ethicists and patient advocates faced the
daunting challenge of convincing clinicians that patients deserve a
role in making their healthcare decisions. This challenge is not over
yet, with recent evidence showing that clinicians still do a
sub-optimal job of informing patients about their treatment
alternatives (Braddock, Fihn, Levinson, Jonsen, & Pearlman, 1997). Our
study shows that a new and important challenge exists for anyone hoping
to help patients make healthcare decisions.
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Appendix
Scenario Text accompanying Table 1 in Study 1
Imagine that you were recently diagnosed with colon cancer,
which is cancer of the bowels. Without treatment, people with your
type of colon cancer usually die within 2 years.
Fortunately, there are two different surgical procedures that can be
performed to treat your cancer. Both surgeries work by removing as
much of the cancer as the surgeons can see. But they differ in the
likelihood of curing the cancer and in the likelihood of causing
complications.
Surgery 1
Surgery 1 cures colon cancer without any complications
in 80%, or 80 out of 100 patients. Surgery 1 does not cure the
colon cancer in 16%, or 16 out of 100 patients, and the patients die
of colon cancer within 2 years.
In addition,
- 1%, or 1 out of 100 patients are cured of their cancer, but must
undergo colostomy, where part of the bowel is removed and
patients have bowel movements into a plastic pouch attached to their
belly.
- 1%, or 1 out of 100 patients are cured of their cancer but
experience chronic diarrhea, involving 6-10 bowel movements a
day, with an occasional need to wake up in the middle of the night to
go to the bathroom.
- 1%, or 1 out of 100 patients are cured of their cancer but
experience intermittent bowel obstruction, which
causes crampy pain in the belly on-and-off for up to 3 hours at a time.
- 1%, or 1 out of 100 patients are cured of their cancer but
experience a wound infection, an open area of the skin at the
surgical scar, which occasionally hurts and drains thick yellow fluid
once in a while. The infection can take up to 1 year to heal.
Surgery 2
Surgery 2 cures colon cancer without any complications
in 80%, or 80 out of 100 patients. Surgery 2 does not cure the
colon cancer in 20%, or 20 out of 100 patients, and the patients die
of colon cancer within 2 years.
Footnotes:
1During the conduct of this
research, Dr. Ubel was recipient of a Presidential Early
Career Award for Scientists and Engineers (PECASE) and Dr.
Zikmund-Fisher was supported by an HSR&D Post-Doctoral
Fellowship from the U.S. Department of Veterans Affairs.
This work was also supported by grants from the National
Institutes of Health (RO1 CA87595, P50 CA101451, R01
HD40789). Correspondence to: Peter Ubel, MD, University of
Michigan, 300 North Ingalls Building, Room 7C27, Ann Arbor,
MI 48109-0429,
paubel@med.umich.edu.
http://www.cbdsm.org.
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