The Effect of Alternative Graphical Displays Used to Present the Benefits of Antibiotics for Sore Throat on Decisions about Whether to Seek Treatment: A Randomized Trial
et al. (2009) The Effect of Alternative Graphical Displays Used to Present the Benefits of
Antibiotics for Sore Throat on Decisions about Whether to Seek Treatment: A Randomized Trial. PLoS Med 6(8): e1000140. doi:10.1371/journal.pmed.1000140
The Effect of Alternative Graphical Displays Used to Present the Benefits of Antibiotics for Sore Throat on Decisions about Whether to Seek Treatment: A Randomized Trial
Cheryl L. L. Carling 0
Doris Tove Kristoffersen 0
Signe Flottorp 0
Atle Fretheim 0
Andrew D. Oxman 0
Holger J. Schu nemann 0
Elie A. Akl 0
Jeph Herrin 0
Thomas D. MacKenzie 0
Victor M. Montori 0
Glyn Elwyn, Cardiff University, United Kingdom
0 1 Norwegian Knowledge Centre for the Health Services , Oslo , Norway , 2 Clinical Research and INFORMAtion Translation Unit, and Department of Epidemiology, Italian National Cancer Institute Regina Elena , Rome , Italy , 3 Department of Medicine, University at Buffalo, Buffalo, New York, United States of America, 4 Division of Cardiology, Yale University , New Haven , Connecticut, United States of America, 5 Department of Internal Medicine, Denver Health and Hospital Authority and University of Colorado Health Sciences Center , Denver , Colorado, United States of America, 6 Knowledge and Encounter Research Unit, Division of Endocrinology and Internal Medicine, Mayo Clinic College of Medicine , Rochester, Minnesota , United States of America
Background: We conducted an Internet-based randomized trial comparing four graphical displays of the benefits of antibiotics for people with sore throat who must decide whether to go to the doctor to seek treatment. Our objective was to determine which display resulted in choices most consistent with participants' values. Methods and Findings: This was the first of a series of televised trials undertaken in cooperation with the Norwegian Broadcasting Company. We recruited adult volunteers in Norway through a nationally televised weekly health program. Participants went to our Web site and rated the relative importance of the consequences of treatment using visual analogue scales (VAS). They viewed the graphical display (or no information) to which they were randomized and were asked to decide whether to go to the doctor for an antibiotic prescription. We compared four presentations: face icons (happy/sad) or a bar graph showing the proportion of people with symptoms on day three with and without treatment, a bar graph of the average duration of symptoms, and a bar graph of proportion with symptoms on both days three and seven. Before completing the study, all participants were shown all the displays and detailed patient information about the treatment of sore throat and were asked to decide again. We calculated a relative importance score (RIS) by subtracting the VAS scores for the undesirable consequences of antibiotics from the VAS score for the benefit of symptom relief. We used logistic regression to determine the association between participants' RIS and their choice. 1,760 participants completed the study. There were statistically significant differences in the likelihood of choosing to go to the doctor in relation to different values (RIS). Of the four presentations, the bar graph of duration of symptoms resulted in decisions that were most consistent with the more fully informed second decision. Most participants also preferred this presentation (38%) and found it easiest to understand (37%). Participants shown the other three presentations were more likely to decide to go to the doctor based on their first decision than everyone based on the second decision. Participants preferred the graph using faces the least (14.4%). Conclusions: For decisions about going to the doctor to get antibiotics for sore throat, treatment effects presented by a bar graph showing the duration of symptoms helped people make decisions more consistent with their values than treatment effects presented as graphical displays of proportions of people with sore throat following treatment. Clinical Trials Registration: ISRCTN58507086 Please see later in the article for the Editors' Summary.
Funding: This study was funded by the Norwegian Research Council (http://www.forskningsradet.no/no/Forsiden/1173185591033). The funders had no role in
study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Abbreviations: HIPPO, Health Information Project: Presentation Online; OR, odds ratio; RIS, relative importance score(s); VAS, visual analogue scale(s).
Relevant, reliable, and accessible information about the effects
of interventions is essential for informed choices about health care.
The manner in which this information is presented affects how it is
understood by both patients and physicians, and their subsequent
health care decisions .
The goal of the Health Information Project: Presentation
Online (HIPPO) was to improve communication of information
about the effects of health care based on randomized trials of
alternative ways of presenting evidence of the effects of health care.
The current study was the first trial in the series that was presented
in cooperation with a weekly health program on the Norwegian
Broadcasting Company, with the goal of helping the public to
learn about medical research and to use research results to inform
The objective of this trial was to determine which format helps
people to make decisions that are most consistent with their values.
A comparison was made of four graphical displays of the effect of
treatment with antibiotics for people with sore throat who must
decide whether or not to go to the doctor to get a prescription
[4,5] to find out which format helps people to make decisions that
are most consistent with their values. In this context, format
includes: the visual display aspects as well as the substantive
content dimensions of information . Values here refers to the
relative desirability of the possible consequences of a health care
intervention, including health outcomes (such as the discomfort of
a sore throat), the burden of treatment (such as the inconvenience
of getting and taking antibiotics), and resource expenditures .
Previous research has used various constructs to evaluate the
effects of graphical displays in communicating treatment effects
[6,812]. Commonly used graphical displays include bar graphs,
pie charts, line graphs, and the use of face icons (i.e., happy/sad).
A review of patient comprehension of information found six
studies that used graphical displays in a medical decision context
. In a comparison of graphical displays among cancer patients,
vertical bars, systematic ovals, and numbers resulted in more
accurate selection of the larger quantity than horizontal bars, pie
charts, and random ovals . Numbers and systematic ovals also
resulted in the most accurate estimation of absolute differences
between quantities, while random ovals were again worst. In other
studies bar charts, thermometer scales and face icons showed no
significant quantitative differences with respect to the level of
decisional conflict aroused [13,14] or perceived value of the
information to decision making, although bar charts were most
commonly preferred . We are not aware of any previous
studies that have compared the effects of different graphical
displays on the extent to which subsequent decisions were
consistent with the decision makers values.
Thus, we designed this study to assess the extent to which the
use of different graphical displays affect choices about whether to
go to the doctor for antibiotics for a sore throat. We chose this
decision because it is common, familiar to most, and because
highquality evidence informs the benefits and downsides of antibiotics
for sore throat [4,5]. It is a preference sensitive decision that is
affected by patients values [15,16]. Thus, among people with a
sore throat, one would expect some degree of correlation between
how important the desirable and undesirable consequences of
taking antibiotics are to them and the likelihood that they would
decide to go to the doctor for antibiotics. In other words, one
would expect that people for whom the benefits of taking
antibiotics were less important and the downsides more important
would be less likely, on average, to decide to go to the doctor than
people for whom the benefits were more important and the
downsides less important.
The CONSORT checklist and the protocol for this study are
available as supporting information; see Text S1 and Text S2.
The study was an Internet-based randomized trial in which
participants were randomized to one of four graphical displays of
information about the effects of antibiotics on the symptoms of
sore throat or to no information (see flow diagram in Figure S1).
The objective was to compare the impact of the graphical displays
on decisions about whether to go to the doctor for antibiotics in
relation to the values of the participants. We used estimates of the
effects of antibiotics for sore throat for Streptococcus-positive,
Streptococcus-negative, and untested patients from a systematic
Interventions and Comparisons
We evaluated these four graphical displays: (1) face icons using
happy and sad expressions displaying the proportion of people
who still have sore throat symptoms on day three, (2) a bar graph
displaying the same information, (3) a bar graph displaying the
difference in the average duration of symptoms, and (4) a bar
graph displaying the proportion of people who have sore throat
symptoms at onset, on day three, and on day seven (Figure 1).
Bar graphs are widely used and familiar to most people. The use
of icons, such as faces, has become popular more recently,
particularly in the context of decision support tools. We initially
considered using a line graph (survival curves for the duration of
symptoms). This display contains the most information relative to
the other alternatives, but following consultations with colleagues,
we concluded that this would be difficult for many people to
understand. We therefore elected to use a second bar graph
presentation that includes similar information to that presented in
a line graph. Day three is the point of maximum benefit and by
day seven most people no longer have symptoms with or without
We planned three main comparisons in advance: (1) different
displays with the same informationface icons versus the bar
graph, both displaying the proportion of people who have sore
throat symptoms on day three, (2) the same display with different
informationthe bar graph displaying the difference in the
average duration of symptoms versus the bar graph displaying the
proportion of people who have sore throat symptoms on day three,
and (3) the same display with additional informationthe bar
graph displaying the proportion of people who have sore throat
symptoms on both day three and day seven versus the bar graph
displaying day three only.
Information about the study was broadcast on Puls, a popular
nationally televised weekly health program with approximately
700,000 viewers (total population of Norway = 4.5 million). We
presented documentation of wide variation in the use of antibiotics
for sore throat in Norway on the program and then invited viewers
to go to our Web site to participate in the study. The Web site was
Upon logging into the Web site, participants were presented
with information about the study and asked to give informed
consent. They viewed a brief scenario in which they were asked to
imagine that they had a sore throat and needed to decide if they
would go to the doctor for antibiotics. Participants were then
Figure 1. Presentations of benefits of antibiotics for sore throat. Based on a systematic review by Del Mar and colleagues  of antibiotic
versus placebo for patients presenting for primary care with symptoms of sore throat.
requested to indicate the relative importance of the discomfort of a
sore throat, side effects of antibiotics, recurrence of sore throat,
and the inconvenience of getting and taking antibiotics using
horizontal 100-point visual analogue scales (VAS) (Figure 2). The
lower and upper anchors of the VAS were labeled Not
important and Very important.
They then viewed one of the four graphical presentations or
received no information, based on random allocation. The system
randomized participants upon log-on, using block randomization
with a looped sequence of 500 presentation assignments consisting
of 100 blocks of five that was generated on http://www.
randomization.com. Participants who had been randomized to
one of the graphical displays were all shown the same textual
information about the downsides of taking antibiotics for sore
throat while the benefit of taking antibiotics was presented by the
allocated graphical display (Figure 3). Next, participants were
asked to indicate whether they would or would not go to the
doctor for antibiotics (Figure 3). They were then asked a few
questions about themselves. Afterward, all participants were
shown all the presentations in a block-randomized sequence,
and were asked which presentation they preferred and which was
easiest to understand. They were then shown detailed
evidencebased patient information about the causes and treatment of sore
throat from a previous study  and asked to reconsider their
original decision and decide again if they would go to the doctor.
Our premise was that the more fully informed second decision
could serve as a benchmark with which the original decisions
could be compared.
Responses from participants who stated they were at least 18
years old and that they were filling in the questionnaire for the first
time were included in the analysis. Participants responses to the
questions on our Web site were saved directly into a database
where the data were stored anonymously. Confidentiality of data
was ensured by not collecting any information that would make it
possible to identify the participants. Voluntary contact information
that some participants supplied in order to be informed of future
studies was stored in a separate database so it was not possible to
couple contact information and study data. Participants were
informed on the consent screen that they could leave the study at
any time and were given the option of choosing to have any data
that they might have entered deleted.
Analysis and Sample Size
For each participant, we calculated a relative importance score
(RIS) by subtracting the sum of her VAS scores for the relative
importance of avoiding the downsides of antibiotics (side effects;
recurrence of sore throat, which is greater with antibiotic
treatment; and the inconvenience of getting and taking antibiotics)
from her VAS score for the relative importance of avoiding the
discomfort of a sore throat. We expected that higher RIS would be
correlated with an increased likelihood of deciding to go to the
In order to compare the effects of the different graphical
displays on the decision to go to the doctor, taking into account
each participants RIS, we used logistic regression with the
decision to go to the doctor (yes or no) as the dependent variable,
and the RIS and allocated display as predictors. The following
model was used:
where D is the decision to go to the doctor or not, G is the
presentation group, S is the RIS value, and G*S is the interaction
between the presentation and the RIS value. To make inferences
about the response within each group and for the comparisons of
groups, we used dummy variable coding with reference
parameterization for the presentation groups, i.e., directly estimating the
difference in the effect between the presentation groups and the
reference group, i.e. bar graph at day 3. Wald tests were used for
the p-values and confidence intervals from the logistic regression,
whereas Chi-square tests were used for comparison of frequencies.
Based on the results of previous studies [18,19], we estimated we
would need about 600 participants per group to achieve 80%
power for each of the three main comparisons (comparing the
linear predictors of the groups) at alpha level 0.0167 after applying
a Bonferroni correction.
Additional comparisons for the difference in log odds at the 1st
and 3rd quartiles and the median values of RIS were planned.
We considered which group made decisions that were the most
consistent with the more fully informed second decision, after
participants have seen all four presentations and been provided
more detailed information. This was done by comparing the linear
predictors for each group for the first decision with the linear
predictor (pooled estimate) for the other four groups for the second
decision using the model above without the interaction term,
which was not statistically significant. We also counted the changes
from the first to the second decision in each group. We used a
logistic regression model to explore whether the respondents did or
did not change their decisions depending on the RIS, presentation
group, and the interaction.
The trial was conducted SeptemberOctober 2004 and stopped
when recruitment tapered off after three weeks. There were 1,760
participants after excluding those under 18 (see flow diagram,
Figure S1). The five groups were similar with respect to sex, age,
education, and VAS scores for their values (Table 1). Sixty-nine
percent were women, compared to 51% in the Norwegian
population. A larger proportion of participants were under 40, a
smaller proportion over 50, and a larger proportion had university
level education, compared to the general population.
Overall, 27.7% of participants chose to go to the doctor on the
first decision (Table 2). There were statistically significant
differences across the five groups (p,0.0001). The group that
viewed the bar graph of duration of symptoms had the smallest
proportion that would go to the doctor (19.7%), closely followed
by the group that received no information (22.7%). The groups
that viewed the faces at day 3 and the bar graph at day 3 had the
largest proportion of people who would go to the doctor (34.6%
and 34.4 % respectively).
Overall, 22.3% decided to go to the doctor on the second, more
fully informed decision (Table 2). Among those who first answered
positively, 28.7% changed their decision from going to not going,
compared to only 3.7% that changed in the opposite direction.
The proportion of participants who changed their decision from
going to not going ranged from 36.7% in the group first shown no
information to 18.8% in the group first shown the bar graph at
days 3 and 7 (p = 0.052).
The largest number of participants (38.4%) preferred the bar
graph of duration, followed by the bar graph at day 3 (30.4%),
while the fewest preferred the faces at day 3 and the bar graph at
days 3 and 7 (14.4% and 16.8%, respectively) (p,0.0001).
Similarly, most participants (37.4%) found the bar graph of
duration easiest to understand, followed by bar graph at day 3
(29.7%), while the fewest found the faces at day 3 and the bar
graph at days 3 and 7 easiest to understand (14.0% and 16.4%,
n = 361
n = 355
n = 351
n = 319
n = 374
N = 1,760
2135.4 (55.4) 2131.9 (60.6) 2128.5 (63.7) 2137.2 (59.2) 2131.4 (59.1) 2132.8 (59.7)
Values (on 100-point
visual analogue scale)c
aFor the Norwegian population the proportion of women and each age group is based on the population over 17 in 2004 . The proportion of people with different
levels of education is based on the highest completed education for people over 16 years old .
bData presented as percentages of n in a given column.
cData presented as mean (standard deviation) for a given presentation group.
Decisions in Relation to Values
There was a clear association between the participants elicited
values (estimated using the RIS) and the likelihood of their
deciding to go to the doctor (Figure 4). As the RIS increased, the
probability of deciding to go to the doctor increased. The groups
shown the faces or the bar graph at day-3 were most likely to
decide to go to the doctor at the median and the 1st and 3rd
quartiles of the RIS values (Table 3). The group shown the bar
graph at days 3 and 7 was slightly less likely to decide to go to the
doctor, whereas the group shown the bar graph of duration of
symptoms was consistently least likely to decide to go to the doctor.
The likelihood of deciding to go to the doctor for the group given
no information was similar to the group shown the bar graph of
duration of symptoms. The interaction between the RIS and
presentation group was not statistically significant (p = 0.46) in the
logistic regression model (Table 4). Thus the null hypothesis of
equal slope of the linear predictors was not rejected, and we
therefore report the odds ratios (ORs). The largest difference
Would go to doctor
Would go to doctor
Change from first to
From go to not go
From not go to go
Data are presented as percentages of number in group.
Bar Graph Duration
between the groups was for the bar graph of duration compared to
the bar graph at day 3, equivalent to OR = 0.39 (95% CI 0.27 to
0.57) (Table 4). An increase of 10 units in RIS increased the odds
Because the interaction term was not statistically significant and
the differences in slopes (Figure 4) may be due to chance, we
removed the interaction term to compare the decisions made by
each group to the more fully informed second decision made by
everyone (Table 5). This model assumes that the slopes are the
same. We then compared the odds of deciding to go to the doctor
based on the first decision for each group with the odds of deciding
to go to the doctor based on the second decision for the pooled
results for the other four groups (Table 5). The only groups that
were not more likely to decide to go to the doctor on the first
RIS = 2183
Face icons, % at day 3
Bar graph, % at day 3
0.23 (0.160.33) 18.6 (13.824.5)
0.28 (0.200.39) 21.9 (16.728.2)
Bar graph, duration of symptoms 0.09 (0.060.15) 8.4 (5.412.9)
Bar graph, % at days 3 and 7
0.19 (0.130.27) 15.7 (11.221.5)
Second decision (all)
0.10 (0.060.15) 8.9 (5.813.4)
0.13 (0.110.16) 11.5 (9.713.7)
Predicted % = proportion deciding to go to the doctor based on logistic regression.
RIS = 2137
0.47 (0.370.60) 32.0 (27.037.4)
0.47 (0.370.59) 31.8 (26.937.1)
0.18 (0.130.24) 14.9 (11.219.6)
0.33 (0.260.44) 25.1 (20.330.5)
0.21 (0.160.29) 17.4 13.422.2)
0.23 (0.210.27) 19.0 (17.021.1)
RIS = 292
0.95 (0.721.26) 48.8 (41.955.8)
0.76 (0.590.99) 43.4 (37.149.8)
0.33 (0.250.44) 24.7 (19.830.4)
0.59 (0.440.79) 37.3 (30.744.3)
0.45 (0.340.59) 30.9 (25.537.0)
0.42 (0.370.47) 29.4 (26.832.1)
Odds (95% CI) Predicted % (95% CI) Odds (95% CI) Predicted % (95% CI) Odds (95% CI) Predicted % (95% CI)
decision were the group that was first presented the bar graph of
duration of symptoms (OR 0.72; 95% CI 0.53 to 0.98) and the
group that was not shown any information for the first decision
(OR 0.93; 95% CI 0.70 to 1.24). The ORs for the other three
groups were all statistically significant (Table 5).
There were no statistically significant differences across the
different presentation groups in the proportions of participants
who changed their initial decision (Table 2). The logistic regression
of whether the respondents changed their decision or not,
depending on the RIS, presentation group, and the interaction,
indicated a marginal interaction between the RIS and the
presentation group shown the faces (p = 0.04). Thus, a simple
logistic regression of the change, depending on the RIS, was
performed per group. The change for the group shown faces was
significant (p = 0.001, for testing b2 = 0) and for the group given no
information (p = 0.02, for testing b2 = 0). This suggests that the
respondents changed their mind irrespectively of their RIS when
shown the additional information.
In the course of 26 days (13 September to 8 October 2004),
there were 4,053 log-ons to the study Web site, resulting in 1,760
usable records. TV recruitment was substantially more successful
than the methods we used in previous studies, including the use of
commercial email lists and advertising [18,19]. In those studies it
took two years to recruit just under 3,000 participants using other
The randomization process generated five comparable groups.
It is not possible to say how similar or different participants
decisions were relative to the general population of Norway.
Bar graph duration of symptoms
versus bar graph % at day 3
Bar graph % at days 3 and 7
versus bar graph % at day 3
aAdjusted overall CI level = 0.95.
Odds Ratio (98.3% CI)a p-Value
Participants were more likely to be female and younger and to
have a higher education than the general population.
The participants largely decided not to go to the doctor for
antibiotics, regardless of the information they received. Overall,
78% said they would not go to the doctor after seeing all four
presentations and receiving more detailed information about the
advantages and disadvantages associated with getting and taking
antibiotics for sore throat.
Different Displays with the Same Information
We compared two different visual displays in this study: bar
graphs and faces, both showing the proportions of people with
symptoms at day 3 with and without antibiotics. The proportions
of participants deciding to go to the doctor in relationship to their
values (RIS) were similar for the two groups shown these two
displays (Table 3), with no significant differences (Table 4).
However, the fewest participants preferred face icons at day 3 or
found that display easiest to understand (14%). The group shown
the display of face icons at day 3 were also most likely to change
(34%) from a positive to a negative decision about going to the
doctor after receiving additional information, including all four
displays. These findings are consistent with those of Edwards and
colleagues in a randomized trial of Web-based information for
people with diabetes . They found that bar charts were most
commonly preferred and least often found difficult, whereas face
icons were more likely to be found unhelpful or patronizing.
The Same Display with Different Information
Our second comparison was of the same display (bar graphs)
with different information: the proportions of people with
Presentation for the First Decision
Odds Ratio (95% CI)
Face icons, % at day 3
Bar graph, % at day 3
Bar graph, duration of symptoms
Bar graph, % at days 3 and 7
symptoms at day 3 and the average duration of symptoms with
and without antibiotics. Of the three comparisons in this study,
this is the only one where we found statistically significant
differences when comparing odds at specific RIS values.
Participants in all of the groups were more likely to decide to go
to the doctor as their RIS increased (Figure 4), as would be
expected. However, participants shown the duration of symptoms
were less likely to decide to go to the doctor across RIS values (OR
0.33 to 0.43), with predicted differences of 13%19% (Table 3).
These differences correspond to number needed to treat of 58;
i.e. for every 58 participants shown the proportions of people
with symptoms at day 3, one additional participant chose to go to
the doctor, compared to those shown the duration of symptoms.
There are at least two possible explanations for this difference.
One is that the effectiveness of antibiotics appears smaller when
considering the average difference in duration of symptoms (63 h
versus 79 h) than when considering the difference in the
proportion of people with symptoms at day 3 (46% versus 66%)
(Figure 1). A second possible explanation is that participants found
this display easier to understand. We also cannot rule out that
small differences in the displays played a role: vertical versus
horizontal bar graphs and three categories in the with
antibiotics bar (better, better because of treatment, and not
better) versus two categories (duration of symptoms and the
difference in duration compared to not taking antibiotics).
Of the four presentations, the bar graph of duration of
symptoms resulted in decisions that were most consistent with
the more fully informed second decision (Table 5). Most
participants also preferred this presentation (38%) and found it
easiest to understand (37%). Participants shown the other three
presentations were more likely to decide to go to the doctor based
on their first decision than everyone based on the second decision.
The Same Display with Additional Information
Our third comparison was of the same display with additional
information: bar graphs displaying the proportion of people with
sore throat at both day 3 and day 7 versus only at day 3. The
proportions of participants deciding to go to the doctor in
relationship to their values (RIS) were 6.1% to 6.7% less for the
group shown bar graphs for both days 3 and 7 (Table 3), but the
ORs for this comparison (0.66 to 0.78) were not statistically
significant (Table 4).
Because most people do not have symptoms by day 7 we
anticipated that fewer participants would decide to go to the
doctor when shown this additional information. A potential
explanation for why the observed differences were small and
inconclusive is that participants found the display with the
additional information difficult to understand.
The group shown the bar graph at days 3 and 7 was less likely to
change from a positive to a negative decision (Table 2). We also
anticipated this, given the additional information provided in this
display, showing that most people are better with or without
antibiotics by day 7. However, this display was the second least
preferred (17%), and the second fewest participants found this
display easiest to understand (16%). The low preference rating for
this display might have been due to information overload,
although in a previous study participants preferred a presentation
with multiple time points for long-term scenarios .
No Information versus Some Information
In this study we used a second more fully informed decision as a
benchmark with which the original decisions could be compared.
The group that was not shown any information for their first
decision was the most likely to change their decision from going to
not going to the doctor, although these differences were not
statistically significant (p = 0.052) (Table 2). The proportion of
participants in the no information group that changed their
decision from to go to not to go to the doctor suggests that a
number of participants (8%) likely started out assuming that the
desirable consequences outweighed the undesirable consequences
and changed their minds when shown the information in Figures 1
Nonetheless, decisions taken by participants in the no
information group appear to be closest to those taken by the
group shown the duration of symptoms and by all of the
participants for the second more fully informed decision
(Table 3). This suggests that the information that was presented
confirmed what most people assumed about the trade-offs between
the desirable and undesirable consequences of getting and taking
antibiotics, and that the presentations showing the proportions of
people with and without symptoms may have to some extent
misinformed participants relative to their second more fully
Applicability of the Findings and Implications
The participants were recruited through a popular nationally
televised weekly health program and needed to have access to the
Internet. Compared to the general population they had more
education (Table 1). It is unclear whether the findings are
applicable to populations with less education [2,18] or to other
countries, although the results are likely widely applicable in
Norway. It is also uncertain to what extent results from the
hypothetical scenario used in this study apply to actual decisions
[21,22], although it is likely that most of the participants would
have experienced sore throat and thus be able to make a realistic
assessment of what they would actually decide. The results are
more directly applicable to patient information accessed over the
Internet, but it seems likely that the differences in decisions
between the groups presented information about the proportion of
people with symptoms at day 3 and the duration of symptoms is
relevant to personal communication as well as to electronic and
Large variation exists in the extent to which antibiotics are
prescribed for sore throat . Clinical practice guidelines for the
management of sore throat also vary with regard to the choice of
evidence, interpretation of the evidence, and recommendations for
diagnosis and treatment [5,23]. Some guidelines consider
diagnosis of group A b-hemolytic streptococcus essential and
consider the prevention of acute rheumatic fever an important
reason to prescribe antibiotics. Other guidelines considered acute
sore throat a self-limiting disease and do not recommend
In most settings in high-income countries such as Norway, the
risk of a serious complication arising from using antibiotics for sore
throat is of the same order as that of rheumatic fever and
suppurative complications of sore throat, all of which are rare .
Thus decisions about whether to prescribe antibiotics depend
largely on the trade-offs between reducing the duration of
symptoms and the downsides of antibiotics, including side effects,
the burden of getting and taking antibiotics, and costs [4,5].
Externalities may also affect decisions, including concerns about
spreading infection on the one hand and antibiotic resistance on
the other, although the level of evidence for both of these is very
Thus, in settings where the risk of rheumatic fever and other
complications of sore throat are rare, decisions whether to take
antibiotics or not are preference sensitive [15,16]. They depend on
the severity of symptoms and the relative importance that
individual patients assign to the desirable and undesirable
consequences of getting and taking antibiotics. The participants
in this study were not a representative sample of the Norwegian
population. Nonetheless, the results suggest that many Norwegians
would choose not to go to the doctor to get antibiotics for a sore
throat (over 75% of participants in this study). However, many
patients still do seek medical help for sore throats, and about half
of those who do receive a prescription for antibiotics in Norway
, despite clinical practice guidelines that recommend that
patients with sore throat should usually be treated symptomatically
without antibiotics .
One study showed that while general practitioners and their
assistants believed that patients prefer visits to the physician to take
tests and receive treatment, rather than have telephone
consultations, the patients state that they appreciate evidence-based
information about sore throat and the recommendation that
testing and consultations were generally not necessary . The
results of this study support that finding and recommendations
that most patients with sore throat do not need to be seen by a
physician and that they should be given good information about
the natural history of sore throat and the effects of antibiotics .
However, the scenario in the current study addressed the decision
of whether to go to the doctor and take penicillin if the doctor
recommended it. For patients who go to the doctor for a sore
throat, the information given to them should reflect an appropriate
diagnosis of whether their sore throat is caused by group A
bhemolytic streptococcus and the increased effectiveness of
antibiotics in people with streptococci growing in the throat .
The implication of this study for clinicians or others who
prepare patient information about antibiotics for sore throat is that
this information is more likely to help people to make
wellinformed decisions if bar graphs of the duration of symptoms are
used. Graphical presentations of the proportions of people with
sore throat using either bar graphs or face icons are likely to result
in decisions that are less consistent with a more fully-informed
decision and more people going to the doctor.
In summary, for people considering whether they should go to
the doctor to get antibiotics for sore throat, presenting the benefit
of antibiotics in terms of the duration of symptoms appears to help
them to make decisions that are most consistent with their own
preferences compared to graphical presentations of the
proportions of people with sore throat. The extent to which these results
can be applied to other decisions is not clear. However, they may
be most likely to be relevant when a treatment has a short-term
benefit that quickly fades away and relatively important
We would like to express our deep appreciation to Jan Arve Dyrnes, Gro
Alice Srensen, and Sandra Haga for programming the Web pages that
were used in this study and providing technical support; to Chris Cates,
Paul Glasziou, and Chris Del Mar for help developing the presentations;
and to Jan Odgaard-Jensen for statistical advice.
ICMJE criteria for authorship read and met: CLC DTK SF AF ADO HJS
EAA JH TDM VMM. Agree with the manuscripts results and conclusions:
CLC DTK SF AF ADO HJS EAA JH TDM VMM. Designed the
experiments/the study: CLC DTK AF ADO EAA JH TDM VMM.
Analyzed the data: CLC DTK. Collected data/did experiments for the
study: CLC SF. Enrolled patients: SF. Wrote the first draft of the paper:
CLC DTK. Contributed to the writing of the paper: CLC DTK SF AF
ADO HJS EAA JH TDM VMM. Participated in the conduct of the trial:
Background. In the past, patients usually believed that
their doctor knew what was best for them and that they had
little say in deciding what treatment they would receive. But
many modern interventions have complex trade-offs.
Patients opinions about the relative desirability of the
possible outcomes of health care interventions depend on
their lifestyle and expectations, and these values need to
be considered when making decisions about medical
treatments. Consequently, shared decision-making is
increasingly superseding the traditional, paternalistic
approach to medical decision-making. In shared
decisionmaking, health care professionals talk to their patients about
the risks and benefits of the various treatment options, and
patients tell the health care professionals what they expect
and/or require from their treatment.
Why Was This Study Done? Shared decision-making can
only succeed if patients know about the treatment options
that are available for their medical condition and understand
the consequences of each option. But how does the
presentation of information about treatment options to
patients affect their decisions? In 2002, a series of
internetbased randomized trials (studies in which participants are
randomly allocated to different treatment groups) called
the Health Information Project: Presentation Online (HIPPO)
was initiated to answer this question. Here, the researchers
describe HIPPO 3, a trial that investigates how alternative
graphical displays of the benefits of antibiotics for the
treatment of sore throat affect whether people decide to
seek treatment. In particular, the researchers ask which
display results in people making a treatment decision most
consistent with their values, i.e., in terms of the relative
importance to them of the treatments desirable and
What Did the Researchers Do and Find? Adult
Norwegians recruited through a television health program
numerically rated the importance of symptom relief and of
several negative consequences (for example, side effects) of
antibiotic treatment for sore throat on the trials Web site.
Relative importance scores (which indicate the participants
values) were calculated for each participant by subtracting
their ratings for the importance of the negative
consequences of seeking antibiotic treatment from his or
her rating for the importance of symptom relief. The
participants were then asked to decide whether to visit a
doctor for antibiotics without receiving any further
information or after being shown one of four graphical
displays illustrating the benefits of antibiotic treatment. Two
bar charts and one display of happy- and sad-face icons
showed the proportion of people with symptoms at specific
times after sore throat onset with and without treatment. A
third bar chart indicated symptom duration with and
without antibiotics. Finally, all the participants were shown
all the displays and other information about sore throat and
were asked to decide again about seeking treatment. The
researchers found a clear association between the
participants values and the likelihood of their deciding to
go to the doctor, and this likelihood depended on which
graphical display the participants saw. People shown
information on the proportion of patients with symptoms
were more likely to decide to visit a doctor than those shown
information on symptom duration. Furthermore, first
decisions reached after being given information on
symptom duration or no information were more consistent
with the fully informed second decision than first decisions
reached after seeing the other displays.
What Do These Findings Mean? These findings suggest
that, for people considering whether to seek antibiotic
treatment for sore throat, a bar graph showing the duration
of symptoms is more likely to help them make a decision
that is consistent with their own values than a bar chart
showing the proportions of people with sore throat
following treatment. The researchers also found that the
bar chart showing symptom duration was preferred by more
of the participants than any of the other representations.
Whether these results can be applied to other health care
decisions or in other settings is not known. However, the
researchers suggest that these findings may be most
relevant to treatments that, like antibiotic treatment of
sore throat, have a short-lived benefit and relatively
Additional Information. Please access these Web sites via
the online version of this summary at http://dx.doi.org/10.
N A PLoS Medicine Editorial discusses this trial and the results
of another HIPPO trial that are presented in a separate
PLoS Medicine Research Article by Carling et al.; details of a
pilot HIPPO trial are also available
N The Foundation for Informed Medical Decision Making (a
US-based nonprofit organization) provides information on
many aspects of medical decision making
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