Informed decision making under technological change
EMGO-institute, Department of Public and Occupational Health, VU University Medical Center, The Netherlands
Daniëlle Timmermans
Informed decision making:
balancing risks and benefits?
INTRODUCTION
• The role of individuals in the decision-making process with regard to the treatment they receive or the health intervention that is offered is becoming increasingly important
• The emphasis is on informed decision making
• Medical decisions need to be sensitive to individual values
• This is especially relevant for new technologies
“Breakthrough of the Year”
• “For 2000, one word sums it up- GENOMES”
– Science
(December 2000)
“ Genetic Defect Doubles Colon Cancer Risk”
Laken SJ et al. Nat Genetics 1997;17:79-83.
• “Researchers have found a new genetic defect present in one of every 17 American Jews that doubles a person's colon cancer risk”.
• “The good news is that
scientists have developed a blood test, available for $200, that can detect this genetic defect. The test is advisable for everyone in the Ashkhenazi
population, whether they have a family history of colon cancer or not.”
• http://www.preventcancer.org/
coloncancer.html
OVERVIEW
• Introduction
• What is informed decision making?
• Decisions and information: balancing the risks?
• Decisions and values: preferences for benefits?
• Implications for practice: balanced decisions?
OVERVIEW
• Introduction
• What is informed decision making?
• Decisions and information: balancing the risks?
• Decisions and values: preferences for benefits?
• Implications for practice: balanced decisions?
WHAT IS INFORMED DECISION MAKING?
• Informed decision making originated in biomedical ethics with the notion of informed consent
• To safeguard patients’ autonomy
• Marked a major departure from the traditional relation between physicians and patients
• Legal requirement
Informed Consent and Informed Decision Making
• Informed consent is not the same as informed decision making (IDM)
• IDM (and also shared decision making) is more process oriented
• and is also focused on producing decisions
consistent with patient’s preferences and values
Informed Decision Making
• When a reasoned choice is made by a reasonable individual
• using
relevant information
about theadvantages and disadvantages of all possible courses of action
• in accordance with the individual’s
beliefs
.» Bekker et al,.Health Technol Asses 1999
Informed Choice
• based on
relevant knowledge
• consistent with the decision-maker's
values
• behaviourally
implemented
.» Marteau,Dormandy,Michie. Health Exp 2001
Informed Decision Making
• understands the disease or condition, the clinical service and its likely consequences,
benefits, risks,
alternatives and uncertainties• understands personal
values and preferences
• makes a decision
consistent
with those preferences» Briss et al. Am J Prev Med 2004
If an individual:
What is needed for patients to make an informed decision?
• He/she must get information
– the options
– the potential outcomes
– the probabilities of these outcomes
• think about what he/she wants
– the preferences for options and outcomes
• and make an informed decision about a health intervention consistent with
preferences
Questions to ask
• Are people capable of making such informed decisions?
– Behavioral decision research suggests that it is mostly not the case (e.g. Gilovich et al. Heuristics and Biases.2002)
• Are people able to rationally appraise the (risk) information provided?
• Are people capable of reliably expressing their preferences and values?
OVERVIEW
• Introduction
• What is informed decision making?
• Decisions and information: balancing the risks?
• Decisions and values: preferences for benefits?
• Implications for practice: balanced decisions?
DECISIONS AND INFORMATION:
BALANCING THE RISKS?
• Risks or probability information is assumed to be
essential for making rational and informed decisions.
• Most patients are unfamiliar with probabilistic thinking and find it hard to understand risks.
Which risk is larger?
Cancer kills:
• 1286 of 10.000 people OR
• 24.14 of 100 people
Most people choose option 1, while the chance of option 1 << option 2
Yamagishi, 1997
Risk perception and decision making of pregnant women regarding prenatal screening
• Women had difficulties in understanding and using numerical risks about prenatal screening
• Data from interviews and questionnaires
– quotes
– relation perceived risk with decision
Hoe groot is de kans op het krijgen van een kind met het syndroom van Down?
Hoe ouder de zwangere is, hoe groter de kans op het krijgen van een kind met het syndroom van Down (zie de onderstaande tabel). Zo is de kans voor een zwangere vrouw van 35 jaar 1 op 400. Dat betekent dat van de 400 kinderen die er uit 35-jarige zwangere vrouwen worden geboren er één het syndroom van Down heeft.
In de grafiek staan de kansen nogmaals weergegeven.
Tabel en grafiek: ‘Kans op het krijgen van een kind met het syndroom van Down’
leeftijd van de zwangere
vrouw
kans op het krijgen van een kind met het syndroom van
Down
in cijfers
(afgerond)
in procenten (afgerond) 25 jaar 1 op 1400 0.07%
30 jaar 1 op 900 0.11%
35 jaar 1 op 400 0.25%
40 jaar 1 op 100 1%
45 jaar 1 op 30 3%
0 1 2 3 4
25 30 35 40 45
leeftijd zwangere vrouw (in jaren) kans (in %)
⇑
⇓
Hoe groot is de kans op het krijgen van een kind met het syndroom van Down?
Hoe ouder de zwangere is, hoe groter de kans op het krijgen van een kind met het syndroom van Down (zie de onderstaande tabel). Zo is de kans voor een zwangere vrouw van 35 jaar 1 op 400. Dat betekent dat van de 400 kinderen die er uit 35-jarige zwangere vrouwen worden geboren er één het syndroom van Down heeft.
In de grafiek staan de kansen nogmaals weergegeven.
Tabel en grafiek: ‘Kans op het krijgen van een kind met het syndroom van Down’
leeftijd van de zwangere
vrouw
kans op het krijgen van een kind met het syndroom van
Down
in cijfers
(afgerond)
in procenten (afgerond) 25 jaar 1 op 1400 0.07%
30 jaar 1 op 900 0.11%
35 jaar 1 op 400 0.25%
40 jaar 1 op 100 1%
45 jaar 1 op 30 3%
0 1 2 3 4
25 30 35 40 45
leeftijd zwangere vrouw (in jaren) kans (in %)
⇑
“I think my chance is 1 in 400, about 25%.” ……
“.. 1 out of 900, that seems large to me. They also mentioned a percentage: 0.11% I think. And that is quite small, I think …..”
“ … Well, I think a little more than 1 out of 1000. But I don’t know exactly any more… And that differs
between persons, and it is like the chance in a lottery.
How much chance you have to win. I mean, I always say: You could be the one, you know. …”
Risk perception of the probability of having a child with Down syndrome
Van den Berg, Timmermans, Kleinveld et al., in prep
0 10 20 30 40 50 60 70 80 90 100
test no test control
1:2 - 1: 200
1:200 - 1:1000*
< 1:1000
Perceived risk of a child with DS of pregnant women BEFORE test offer
(in percentages)
*Nicolaides KH et al. Ultrasound Obstet Gynecol 2005; 25: 221-226.
0 10 20 30 40 50 60 70 80 90 100
test no test control
1:2 - 1: 200 1:200 - 1:1000
< 1:1000
Perceived risk of a child with DS of pregnant women AFTER test offer
(in percentages)
• Risk information provided to people may not have much effect on individuals’ (strongly held) beliefs
» see also Farrell et al Eff Clin Pract 2002
• Women do not use the risk information because they: – do not understand the risks
– think the risks are not relevant for their decision
• Therefore, use risk formats which are easier to understand, e.g.:
– natural frequencies – use graphics
Type of
information Examples How to foster insight
Single event probabilities
"You have a 30%
chance of a side effect from this drug"
Use frequency statements:
"Three out of every 10
patients have a side effect from this drug"
Gigerenzer & Edwards. BMJ 2003
See also: Gigerenzer: Reckoning with risk. Learning to live with uncertainty. 2002
Natural frequencies
There is another reason for the low
correlation of perceived risk with decisions
• “ Well, I mean, if your cholesterol is OK it means that there’s no more risk of cardiovascular disease, isn’t that right? You may say, it’s one in a hundred. But what if I’m that one? One in a hundred means
nothing to me. It’s always fifty-fifty in a way.”
• Van Steenkiste, Van der Weijden, Timmermans et al. Pat Educ Couns, 2004
• People code risk information qualitatively
• and they tend to focus more on the outcomes than on the probabilities
– and have emotions about these outcomes – which arise as a reaction to mental images
Binary perception of risk
One’s mental image of getting a child with Down syndrome is likely to be the same whether one’s chance is 1 out of
1500 or 1 out of 40
• Mental images are discrete
• Feelings about risk are thus largely insensitive to changes in probability
– especially in the broad midrange of probabilities
• whereas cognitive evaluations are not
• As a result, feelings about risk and cognitive risk perceptions often diverge.
Loewenstein et al., Psychological Bulletin 2001
Damasio: Descartes Error: emotions, reasons and the human brain 1994
I: What do you think of the risk of a miscarriage?
R: It is quite logical there is a risk, you stick a needle in something which is supposed to stay whole. So,
you can’t avoid that. But my feeling says it is just very large, that chance. …. However, in fact the chance is very small, I know that, but my feeling says it is very large. So that is why I say I am not very keen on it. (i.e.
prenatal testing).
Van den Berg, Timmermans, Kleinveld et al., in prep.
Conclusion
• Although much can be gained from presenting risk information in formats that are easier to understand by individuals, people’s emotional reactions towards risks is an important factor that needs more attention
OVERVIEW
• Introduction
• What is informed decision making?
• Decisions and information: balancing the risks?
• Decisions and values: preferences for benefits?
• Implications for practice: balanced decisions?
DECISION AND VALUES:
PREFERENCES FOR BENEFITS?
• A key component of making informed decisions is that decisions are in accordance with one’s values
• Assumption: people have articulated values
• However, preferences often are constructed
» e.g. Slovic. American Psychologist 1998
Attitudes of pregnant women deciding for prenatal screening
• Attitudes can be considered a reflection of one’s values (Marteau et al. 2001; Michie et al. 2002)
• Attitudes were measured before and after the decision was made (but before test was done).
• Women’s attitudes were not constant but changed as a function of the decision they made.
Neutral attitude
2 2,5 3 3,5 4
t1 t2
attitude
sure acceptors (n=161) probable acceptors (n=86) doubters (n=28)
probable decliners (n=76) sure decliners (n=234)
Attitude scores of women with a neutral attitude at T1, as a function of their intended decision to
have screening done or not. Scale is from 1 to 5
Kleinveld, Timmermans, Van den Berg et al. in prep.
Questions
• What made women change their attitudes?
• What came first: the decision or the change in attitude?
• Which attitude is the “real” attitude?
• Or is change in attitude = decision?
Choosing a poster
• People were asked to evaluate two types of posters
– art posters
– humorous posters
• One group was asked to write down, privately and anonymously, why they felt the way they did about each poster
• All participants then rated their liking for each poster and chose one
• Six months later, more posters were still on the wall of the group who did NOT write down reasons
» Wilson et al. 1993
• Thinking about reasons has been found to change people’s attitude
• When thinking about reasons people focus on reasons
that are accessible in memory, plausible as causes of their feelings and easy to verbalize
• However, these reasons are often unrepresentative of the actual causes of attitudes
» TD Wilson: Strangers to ourselves. Discovering the adaptive unconsciousness. 2002
• Analysing preferences by making list of pluses and minuses, should best be avoided when people are not very knowledgeable (which is often the case with medical decisions)
• We should not analyse the information in an overly deliberate conscious manner.
• “The trick is to gather enough information to develop an informed gut feeling and then not to analyse that feeling too much.” Wilson, 2002
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OHRI
Welcome to Patient Decision Aids - part of the Ottawa Health Research Institute, affiliated with The Ottawa Hospital and The University of Ottawa.
The Patient Decision Aids research program was developed to help patients and their health practitioners make "tough" healthcare decisions. "Tough" healthcare decisions may have many options, uncertain outcomes or benefits and harms that people value differently.
Professor Annette O'Connor, awarded Canada's first Research Chair in Health Care Consumer Decision Support, leads an international team that designs and tests decision aids and training programs for patients and health practitioners:
• Ottawa Personal Decision Guide
An online tool for any "tough" decision.
• Ottawa Decision Aids
A list of the decision aids developed and evaluated in Ottawa.
• A to Z Global Inventory of Patient Decision Aids
Conclusions
• If preferences are constructed in the process of informing and making a decision, it could be argued that the
rationale behind the informed model of decision making cannot be defended.
• When asking patients and health consumers to think about their preferences and values, this will not
necessarily reflect people’s real preferences, especially not when it concerns non familiar situations.
OVERVIEW
• Introduction
• What is informed decision making?
• Decisions and information: balancing the risks?
• Decisions and values: preferences for benefits?
• Implications for practice: balanced
decisions?
What is needed for patients to make an informed decision?
• He/she must understands the information
• think about what he/she wants
• and make an informed decision consistent
with his/her preferences
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
adequate knowledge
deliberated decision
consistent with one's
values
informed decision
Informed decision prenatal screening:
In percentages
IMPLICATIONS FOR PRACTICE:
BALANCED DECISIONS?
• How should we present risk information?
– Natural frequencies? Graphics? Or …?
• How much information is needed for an informed decision?
– What is the relevance of risk information? Is it a decision about the risks of prenatal testing or is it about what kind of pregnancy a woman wants?
IMPLICATIONS FOR PRACTICE:
BALANCED DECISIONS?
• How can we reliably estimate a person’s values?
– What are the values our decisions should be consistent with? How do we know they are the “real” values?
• How much deliberation is needed?
– When will decision aids aimed at helping us to consciously trading off risks and benefits really lead to “better” decisions?
– What role does intuition play in informed decision making? Is there something like intuitive informed decision making as opposed to deliberate informed decision making?
