EBM

Question 1

List the types of bias.

Answer 1

Types of bias:

1 - Selection:

• Sampling
• Response
• Healthy worker / reproducer

2 - Performance

3 - Allocation

4 - Information:

• Recall
• Recording
• Interviewer
• Lost to follow-up
• Social acceptability

5 - Review

6 - Verification

7 - Attrition

8 - Publication

9 - Spectrum

10 - Contamination

11 - Confounding (a variable that influences both the dependent and independent variable, and can therefore cause or prevent the outcome of interest).

12 - Confirmation (no extra card on this - bias that occurs when more weight is given to evidence that confirms the researchers’ beliefs, and undervalues evidence that could disprove it).

Question 2

Define selection bias.

Answer 2

Selection bias is bias that occurs when groups in a study differ systematically from the population of interest.

It comprises 3 subtypes:

1 - Sampling bias is bias that occurs due to differences in sampling probability amongst eligible participants.

2 - Response bias is bias that occurs when non-responders differ to responders.

3 - Healthy worker / reproducer bias is bias that arises from the tendency of a study population to be healthier than the population of interest.

Question 3

Define performance bias.

Answer 3

Performance bias is bias that occurs due to systematic differences between the amount of attention received from researchers, or exposure to factors other than the intervention of interest, between groups.

Question 4

Define allocation bias.

Answer 4

Allocation bias is bias that occurs due to systematic differences in how participants are assigned to treatment and control groups.

Question 5

Define information bias.

Answer 5

Information bias is bias that occurs due to systematic differences in how outcomes are measured in treatment and control groups.

It comprises 5 subtypes:

1 - Recall bias is bias that occurs when participants in a study are more or less likely to accurately recall information regarding their exposure depending on their outcome, or vice versa.

2 - Recording bias is bias that occurs due to differences in the level of availability of medical information between groups with and without an outcome or exposure of interest.

3 - Interviewer bias is bias that occurs due to distortion of the response given by an interviewee due to preconceived judgement on behalf of the interviewer.

4 - Lost to follow-up bias is bias that occurs due to differences between individuals that are lost to follow-up and those that are successfully followed-up (similar to attrition bias).

5 - Social acceptability bias is bias that occurs due to the tendency of participants to answer questions in a manner that will be viewed favourably by others.

Question 6

Define verification bias.

What is the difference between partial and differential verification bias, and how do they impact on the results?

Answer 6

• Verification bias is bias that occurs when an index test is not verified using the gold standard procedure.
• Partial verification bias occurs when some participants do not receive any reference standard test, whilst others do. This often occurs when a more invasive or harmful reference standard is reserved for those that receive a positive index test.
• Partial verification leads to over-verification of positive results relative to negative results. This means that negative results are less likely to be included in the results, leading to an overestimate of the sensitivity (underestimation of false negatives relative to true positives) and an underestimate of the specificity (underestimation of true negatives relative to false positives).
• Differential verification bias occurs when different reference standards are used for different participants. This often occurs when a more invasive or harmful (and more accurate) reference standard is reserved for those that receive a positive index test, and vice versa.
• The effect of differential verification bias on the estimate of sensitivity and specificity of the index test depends on the difference in accuracy of the two reference standard tests.

Question 7

Define attrition bias.

Answer 7

Attrition bias is bias that occurs due to differences in the number and type of participants that are lost from different groups.

Question 8

Define publication bias.

Answer 8

Publication bias is bias that occurs when the outcome of research affects its likelihood of being published.

Question 9

Define spectrum bias.

Answer 9

Spectrum bias is bias that occurs when a diagnostic test is studied in a group that is different to the population for which the test is designed.

*Don’t forget to also check disease status as well as other baseline characteristics.

Question 10

Define contamination bias.

Answer 10

Contamination bias is bias that occurs when members of the control group are inadvertently exposed to the intervention.

Question 11

What are the two overarching categories of epidemiological study?

What is the difference between these study types?

Answer 11

• The two overarching categories of epidemiological study are descriptive and analytic.
• Descriptive studies are those which describe one or more variables in a sample without regard to any hypothesis.
• They answer ‘what’, ‘who’ and ‘when’ questions and are typically hypothesis-generating.
• Analytic studies are those which attempt to quantify an association between an exposure and an outcome to test a specific hypothesis.
• They answer ‘how’ and ‘why’ questions and can be split into observational or interventional.

Question 12

List all of the subtypes of epidemiological study and state whether they are descriptive or analytic.

Answer 12

Types of epidemiological study:

Mixed (descriptive or analytic):

1 - Ecological study.

2 - Cross-sectional study.

Descriptive:

1 - Case report.

Analytic:

1 - Cohort study.

2 - Case-control study.

3 - Clinical trial.

Question 13

What is an ecological study?

How is this study design useful?

Answer 13

• An ecological study is any descriptive or analytic study that utilises comparison of groups rather than individuals.
• It is useful when individual-level data would be difficult to collect, such as the effect of air pollution, or of legislation.

Question 14

What is a case report?

Answer 14

A case report is a type of descriptive study that illustrates novel or atypical features identified in clinical practice.

Question 15

What is a cross-sectional study?

What are its advantages and disadvantages?

Answer 15

• A cross-sectional study is any descriptive or analytic study that utilises data taken from a single point in time.

Advantages:

1 - Inexpensive.

2 - Quick.

Disadvantages:

1 - It is hard to make causal inferences from cross-sectional data since the time sequence of exposure and outcome cannot be assessed.

2 - It is difficult to establish a true association with age since individuals born in different years may have had different exposure experiences as they age.

3 - It is only possible to analyse prevalent cases in cross-sectional studies (also true for case-control studies). Prevalent cases include a mixture of incidence and survival, meaning they include factors that determine duration of illness.

Question 16

What is a cohort study?

What are its advantages and disadvantages?

Answer 16

• A cohort study is a type of observational study in which a group of individuals who are defined on the basis of their exposure are either:

Followed-up over time to determine who develops the outcome of interest (prospective), or

Already followed-up and are assessed on the basis of their outcome (retrospective).

Advantages:

1 - Cohort studies are useful for following-up rare exposures.

2 - Cohort studies are effective in establishing cause and effect since exposure is measured before disease occurrence.

3 - There is no limit to the number of diseases for which the risk of occurrence may be related to the exposure.

4 - Cohort studies are able to make use of incident cases, which are preferable to prevalent cases (because prevalent cases include a mixture of incidence and survival, meaning they include factors that determine duration of illness).

5 - Cohort studies can eliminate recall bias if exposure is ascertained from another source (such as medical records) at the start of the study.

Disadvantages:

1 - Cohort studies are not useful for studying rare diseases because few participants will develop the disease.

2 - Cohort studies involve large numbers of people over long periods of time and so are expensive and logistically difficult.

3 - Cohort studies are limited to studying one exposure.

Question 17

What is a case-control study?

What is a nested case-control study?

What are the advantages and disadvantages of a case-control study?

Answer 17

• A case-control study is a type of observational study in which a group of individuals who are defined on the basis of their outcome are retrospectively compared to a group of controls in relation to their level of exposure prior to developing their outcome.
• A nested case-control study is one in which:

1 - The cases are nested within a well-defined cohort (ideally population-based), for which the level of ascertainment of the cases is known to be very high.

2 - A specified number of controls is matched to each case. This leads to a minor loss in statistical efficiency but significantly reduces cost and streamlines data analysis.

Advantages of case-control studies:

1 - Case-control studies are useful for studying rare diseases.

2 - There is no limit to the number of exposures that can be related to the risk of occurrence of the outcome.

Disadvantages of case-control studies:

1 - Case-control studies are prone to recall bias as they may require the participants to recall information regarding previous exposure.

2 - Case-control studies are limited to studying a single disease at a time.

3 - It is only possible to analyse prevalent cases in cross-sectional studies (also true for cross-sectional studies). Prevalent cases include a mixture of incidence and survival, meaning they include factors that determine duration of illness.

Question 18

What is a clinical trial?

List 4 key features of clinical trials.

What are its advantages and disadvantages?

Answer 18

• A clinical trial is a prospective interventional analytic study which aims to measure the association between an intervention and an outcome in human participants.
• Key features of clinical trials include:

1 - Randomisation (if it is a randomised control trial).

2 - Concealment of allocation.

3 - Blinding.

4 - Intention to treat (ITT) analysis.

Advantages:

1 - Produces the strongest empirical evidence from which to make causal inferences.

2 - Can minimise sources of bias and confounding if performed correctly.

Disadvantages:

1 - Logistically difficult and expensive to carry out owing to its prospective design and often large sample size.

2 - Ethical requirement for equipoise (the assumption that it is unknown as to whether the intervention would favourably affect the outcome of either the control or experimental group).

Question 19

Define review bias.

What type of data are most prone to review bias?

Answer 19

• Review bias is bias that occurs when the interpreter of the index test is not blinded to the results of the reference standard or vice versa.
• This potential source of bias is more likely to affect data that are subjective (e.g. clinical examination findings, interpretation of imaging tests) than data that are objective (e.g. blood test results).

Question 20

List the Bradford-Hills criteria for causation.

Answer 20

Bradford-Hills criteria for causation:

1 - Biological plausibility

2 - Time

• Did the exposure precede the outcome?

3 - Strength of association

• The stronger the association of an exposure with disease occurrence, the harder it is to conceive of likely confounders which might explain the association.

4 - Dose-response relationship / biological gradient

5 - Consistency

• The results should be consistent with other studies in different populations, places and times.

6 - Specificity

• If the supposed cause is associated with one disease only, a causal relationship is more likely.

7 - Coherence

• The findings should not contradict what is already known about the biology of the disease.

8 - Experiments

• Is the study properly conducted? E.g. randomisation.

9 - Analogy

• Are similar agents known to cause similar outcomes in similar circumstances?

Question 21

What is I squared?

Answer 21

I squared measures the degree of inconsistency across studies in a meta-analysis that is not accountable by chance.

*A measure of heterogeneity

Question 22

What is incidence, point prevalence, period prevalence, absolute risk, attributable risk (AKA risk difference), relative risk and odds ratio?

Answer 22

• Incidence is (number of new cases) / (total number of person years at risk during the study).
• Point prevalence is (number of cases at a particular time) / (total population at risk of disease at the same point in time).
• Period prevalence is (number of cases during a particular time period) / (total population at risk of disease during the same time period).
• Absolute risk is (number of new cases) divided by (number of person-years accumulated). It describes the risk of a group developing an outcome within a specified time period. It is NOT a comparative measure.
• Attributable risk (AKA risk difference) is (risk in exposed) minus (risk in unexposed). It describes the additional absolute risk that is attributable to exposure.
• Relative risk is (incidence of disease among exposed individuals) divided by (incidence of disease among unexposed individuals). It is used to compare risk between groups or to calculate the effect of an exposure on risk.
• Odds ratio is calculated in the same way as relative risk but uses prevalent cases (where incident cases are not available, e.g. in cross-sectional or case-control studies). It is used to approximate the relative risk.

Question 23

How can confounding factors be adjusted for in statistical analysis?

Answer 23

Adjustment for confounding can be achieved through the use of a suitable regression model:

• Unmatched case-control study - logistic regression.
• Matched case-control study - conditional logistic regression.
• Cohort study - logistic / linear / cox / poisson regression.

Question 24

What is reflexivity?

Answer 24

Reflexivity is the process of a researcher critically examining the potential influence of their professional background, experience and personality on:

• The formulation of research questions.
• Data collection.
• Relationship with participants.

Question 25

What is an iterative method of data collection?

Answer 25

• Iterative data collection is a method used in qualitative research that includes repeating cycles of data collection and analysis.
• This may also include changing the study methods on the basis of new findings or modifying the research question.
• Iterations are performed until additional data collection no longer adds new insight - this is the point of ‘saturation’.

Question 26

Describe the sampling process in qualitative research.

Answer 26

• Sampling in qualitative research is most often purposive. This means that people are selected for a particular demographic or experience to answer a specific research question, rather than for representativeness. It emphasises:

1 - Recruiting beyond those individuals for whom taking part is easiest (i.e. not just middle class people with time to spare).

2 - Looking for information-rich participants, ensuring that a range of perspectives are covered on a particular issue.

Question 27

List the main approaches to qualitative research.

Answer 27

Main qualitative approaches:

1 - Grounded theory.

• Involves developing theories which are ‘grounded’ in data that has been systematically collected and analysed. It is used to uncover social processes such as relationships and behaviours of groups.

2 - Ethnography.

• Involves describing or interpreting a cultural or social group.

3 - Case study.

• Involves in-depth analysis of a single case / multiple cases.

4 - Narrative.

• Involves eliciting meaning of experiences expressed as stories of individuals.

5 - Phenomenology.

• Involves understanding the essence of experience of a phenomenon.

Question 28

List the ‘hierarchy’ of types of evidence.

Answer 28

Hierarchy of evidence (descending order):

1 - Systematic reviews and meta analyses

2 - RCTs

3 - Cohort study

4 - Case-control study

5 - Cross-sectional study

6 - Case series

7 - Consensus / expert opinion

• Qualitative and DTA evidence do not belong in this hierarchy.

Question 29

List 3 consequences of inappropriate diagnostic testing.

Answer 29

Consequences of inappropriate diagnostic testing:

1 - Waste of money that could be better used elsewhere.

2 - Anxiety, discomfort, pain and adverse effects of testing.

3 - Increased number of total diagnostic errors:

• False positive results cause unnecessary distress and anxiety, further tests and unnecessary treatment.
• False negatives wrongly reassure patients, result in disease going untreated and may result in harm to others (e.g. with infectious disease).

Question 30

What are the components of a diagnostic test accuracy question?

Answer 30

Components of a diagnostic test accuracy question:

• Participants (presentation and prior tests).
• Index test (may also be comparing the same test but with differences in operator experience or technology - e.g. US in primary care vs US in A&E).
• Target disorder (the conditions we want the index test to identify - may also include the cause of the target disorder in the study question. This is useful to help minimise spectrum bias; e.g. abdo pain due to constipation is more likely to occur in primary care whereas abdo pain due to acute pancreatitis is more likely to occur in A&E.
• Reference standard (the most accurate method available of detecting the target disorder).
• PITR instead of the usual PICO

Question 31

What are GRADE tables?

What are the domains of GRADE tables?

Answer 31

• GRADE tables present the number, type and quality of studies for each clinical question / guideline outcome.
• GRADE has 5 domains, each of which can be rated down from a starting point of ‘high’ by one level to ‘moderate certainty’ or two levels to ‘low certainty’.
• The overall certainty of evidence per clinical question / outcome (high / moderate / low / very low) is the sum of number of downgrades across the 5 domains (e.g. if the risk of bias is downgraded by one and the indirectness is downgraded by one, the overall downgrade is 2 - from ‘high’ to ‘low’ certainty).

GRADE domains include:

1 - Risk of bias (informed by the evidence hierarchy and critical appraisal of individual studies included in the guideline).

2 - Imprecision (width of CI - what is the worst possible estimate of effect)?

3 - Inconsistency (how similar are the results of individual studies? Is there CI overlap? For SRs what is the I squared?).

4 - Indirectness (applicability of evidence to the population and setting of interest (PICO).

5 - Publication bias (potential effects of ‘missing’ studies on estimates of effect).

Question 32

For search strategies aiming to address a clinical question, list the order in which the different types of secondary and primary evidence should be accessed.

Answer 32

For search strategies aiming to address a clinical question, the order of access is:

1 - Clinical guidelines.

2 - Evidence summaries (e.g. clinical knowledge summaries).

3 - Systematic reviews.

4 - Primary sources (RCT>cohort>case-control>cross-sectional>case series>consensus).

Question 33

What is an evidence summary?

Answer 33

• An evidence summary is a review of evidence that summarises existing evidence and identifies any gaps
  in the evidence.
• They are often based on current clinical guideline recommendations and systematic reviews (which are, themselves, a form of evidence summary).

Question 34

List the key characteristics of clinical guidelines.

Answer 34

Key characteristics of clinical guidelines include:

1 - A comprehensive review of evidence, which:

• Is driven by the need for information (not restricted by evidence type / quality).
• Evaluates the confidence in the evidence, e.g. using a GRADE assessment.

2 - An economic analysis.

3 - Multiple expert opinions.

4 - Addressing multiple clinical questions covering an entire disease management pathway (diagnosis, treatment and rehabilitation).

5 - Engaging stakeholders - groups representing all those who have a vested interest in the guideline output (not necessarily ‘experts’). E.g. this may include local health organizations and national organizations representing commercial, professional, service, and patient groups.

Question 35

Describe a method for clinical guideline appraisal.

How does this differ from GRADE?

Answer 35

AGREE-II is an appraisal tool for clinical guidelines. It consists of 6 domains:

1 - Scope and purpose.

2 - Stakeholder involvement.

3 - Rigour of development.

4 - Clarity of presentation.

5 - Applicability.

6 - Editorial independence.

• This is different to GRADE in that GRADE only considers the certainty of evidence, whereas AGREE-II considers the whole guideline (not just limited to an appraisal of the evidence).

Question 36

List 3 advantages of clinical guidelines.

Answer 36

Advantages of clinical guidelines:

1 - Facilitate shared decision-making between practitioner and patient.

2 - Facilitate sharing of evidence base for clinical practice between practitioners.

3 - A tool for quality assurance activities (e.g. for clinical audits, care pathways and performance indicators).

Question 37

List 9 key factors that must be addressed when designing an RCT.

Answer 37

Key factors that must be addressed when designing an RCT:

1 - Choice of outcome measure.

2 - Ethics (equipoise - discussed in a previous card). Common example: ORACLE trial.

3 - Choice of control.

4 - Sample size.

5 - Randomisation.

6 - Allocation concealment.

7 - Intervention.

8 - Blinding.

9 - Assessment of outcomes.

*Each of these factors are discussed in next cards.

Question 38

List the qualities of a good outcome measure for an RCT.

Answer 38

Qualities of a good outcome measure for an RCT:

1 - The outcome is relevant to patients (e.g. survival, QoL or a clinical measure such as blood pressure).

2 - If the outcome is a proxy measure, it must be linked with high certainty to the outcome of interest.

3 - The outcome measure is reliable (has the ability to produce consistent, reproducible estimates of the true effect).

4 - The outcome measure is valid (measures the construct that it claims to measure).

5 - The outcome is responsive (can detect changes in the construct to be measured over time).

Question 39

List 4 types of controls in RCTs.

Answer 39

Types of controls in RCTs:

1 - Usual care.

2 - No treatment.

• Only if there is no usual care.

3 - Placebo.

• Useful for blinding participants and researchers, and to distinguish placebo effects from intervention effects.

4 - Sham intervention.

• Useful for blinding participants.

Question 40

What is the purpose of randomisation in RCTs?

Answer 40

• Randomisation in RCTs ensures that known and unknown confounders are equally distributed among control and intervention groups (provided the sample size is large enough).
• Consequently, randomisation reduces selection bias.

Question 41

List 3 characteristics of confounding variables in RCTs.

Answer 41

Characteristics of confounding variables:

1 - It is associated with both the outcome and exposure.

2 - It must not be on the causal pathway between the intervention and the outcome.

3 - Its distribution must differ between groups for confounding to take place (prevented by randomisation).

Question 42

List 2 factors that might influence patient allocation in RCTs if there is no allocation concealment.

Why is allocation concealment necessary?

Answer 42

Factors that might influence patient allocation include:

1 - Doctors’ beliefs about the suitability of an intervention for a particular patient.

2 - Patient preference.

• Allocation concealment is necessary to prevent allocation bias (an imbalance in the characteristics of participants between the control and intervention groups due to differences in allocation).

Question 43

List 3 potential complications that may arise with interventions in RCTs.

Answer 43

Complications that may arise with interventions in RCTs:

1 - Non-adherence, e.g. due to side-effects or required effort and commitment).

2 - The comparator group gets extra treatment from the researchers, causing performance bias. This may arise due to:

• The control group get the treatment anyway (contamination).
• The control group seek other complementary treatments.
• Healthcare professionals provide additional care due to sympathy over not receiving the intervention.

3 - The intervention group gets extra treatment from the researchers (performance bias).

• This may arise due to more regular contact with healthcare service, which could lead to more early detection of problems.

Question 44

What are the degrees of blinding in an RCT?

What are the advantages of blinding participants, healthcare professionals and researchers in RCTs?

Answer 44

Blinding can be:

1 - Unblinded / open label.

2 - Single-blinded (only the participant is blinded).

3 - Double-blinded (participants, researchers and healthcare providers are blinded).

4 - Triple-blinded (participants, researchers, healthcare providers and statisticians are blinded).

• Blinding the participants helps avoid disappointment for the ‘usual care’ group and means they don’t change their behaviour or response to the intervention.
• Blinding the healthcare professionals avoids compensatory activities for the ‘usual care’ group and complementary treatments for the intervention group.
• Blinding the researchers avoids any bias in measuring or interpreting outcomes.

Question 45

What is an intention to treat (ITT) analysis?

What are the advantages and disadvantages of this technique?

Answer 45

• Intention to treat (ITT) analyses are those which group participants according to the group that they were assigned to at the start of the trial, regardless of whether or not the intervention / control was received as intended.
• This gives the effect of assignment to the interventions at baseline.
• Advantages of ITT include:

1 - Negating contamination bias.

2 - Preserving the effect of randomisation, which in turn reduces selection bias.

• Disadvantages of ITT include:

1 - For full ITT analyses, even those participants that were lost to follow-up must be included. This means that missing follow-up data has to be imputed, meaning a scientifically plausible value for the follow-up data has to be created. This is either made on the basis of the last value carried forward, or by taking into account participant characteristics of those lost to follow-up and predicting their outcomes on the basis of other similar participants that were successfully followed-up. This is a source of error.

2 - ITT analyses result in an under-estimate of the true effect size.

Question 46

What is a per-protocol analysis?

When is this used?

Answer 46

• A per-protocol analysis is an analysis of RCT results that only includes the participants who adhered to their randomisation assignment.
• This gives the effect of adhering to the interventions as specified in the trial protocol (the ‘per-protocol effect’).
• This should be used as an exploratory analysis (not the main analysis).

Question 47

List 2 factors that might give rise to bias in assessing outcomes in RCTs.

Answer 47

Factors that might give rise to bias in assessing outcomes in RCTs:

1 - Lack of blinding. This makes the participant’s, researchers’ and statisticians’ expectations susceptible to influencing outcomes.

2 - Differences in the method used to assess outcomes between control and intervention groups (information bias).

Question 48

What are cluster RCTs?

When are they useful?

Answer 48

• Cluster RCTs are those which randomise groups of participants rather than individuals.
• They are useful when there is an intervention with a high risk of contamination such as:

1 - If the intervention requires a healthcare practitioner to change their behaviour (e.g. the study ‘training primary healthcare professionals in behaviour change counselling for smoking, alcohol, diet and exercise’ randomised general practices rather than the practitioners).

2 - If the intervention is delivered in a situation where it would be impossible for some individuals to get one intervention and others something different (e.g. ‘sexual health education programme in schools - randomise schools or classes).

Question 49

What is trustworthiness in qualitative research?

What factors does it include?

Answer 49

Trustworthiness includes factors that make a rigorous qualitative study. This includes:

1 - Credibility - the equivalent of internal validity. Credibility consists of:

• Triangulation (using different data sources, investigators and methods of data collection).
• Prolonged engagement (investing sufficient time).
• Persistent observation (identifying relevant elements of the problem).
• Member check (feeding back data to participants).
• Demonstration that the research has fairly represented the data by making sure all data available was analysed.
• The use of multiple coders to ensure the analysis is not one-dimensional.

2 - Reflexivity (see card 24).

3 - Relevance - does the study:

• Explore an important issue within its social context?
• Give voice to patients, carers or the disempowered?
• Provide understanding of values and experiences where they are different from practitioners?
• Help to see healthcare as embedded in everyday life?
• Influence clinical practice?

4 - Transferability - does the study describe in sufficient detail the context in which it was carried out?

5 - Transparency.

Question 50

What are process measures?

Answer 50

• In RCTs, process measures are measures of specific steps in a process that lead (either positively or negatively) to a particular outcome metric.
• E.g. one of the process measures for length of inpatient stay might be the amount of time that passes between when the physician ordered the discharge and when the patient was actually discharged.

Question 51

What is the difference between type 1 and type 2 error?

Answer 51

• Type I error is rejecting the null hypothesis when it is actually true.
• Type II error is accepting the null hypothesis when it is actually false.

Question 52

What is the difference between internal and external validity?

Answer 52

• Internal validity refers to the confidence with which a causal relationship can be established between an intervention and an outcome within a study.
• External validity is the applicability / generalisability of study results to settings other than that in which they were originally found.

Question 53

List the purposes of eligibility criteria in clinical trials.

Answer 53

1 - Eligibility criteria influence recruitment by eliminating confounding factors.

2 - Eligibility criteria convey information relating to external validity.

Question 54

What is the three talk model for shared decision making?

Answer 54

The three talk model for shared decision making describes 3 stages (+ a deliberation stage) of the consultation process:

1 - Choice talk.

• This involves making sure the patient knows that reasonable choices are available.

2 - Option talk.

• This involves comparing alternatives and using risk communication principles.

3 - Deliberation.

• This involves eliciting patient reactions and preferences, and discussing pros and cons.

4 - Decision talk.

• This involves arriving at decisions that reflect the informed preferences of the patient, guided by the doctor.

Question 55

List 3 advantages of shared decision making.

Answer 55

Advantages of shared decision making include:

1 - Reducing health inequalities.

2 - Making patients less likely to sue.

3 - Reducing medicalisation (because patients tend to choose the least invasive / disruptive course of action) - e.g. fewer men choose to have PSA testing.