Evidence-Based Decision Making
Evidence-Based Decision Making is a three-hour team process for reaching a proposed decision on a complex problem by working through four steps: ask, acquire, appraise and aggregate. Teams turn a practitioner's account of the problem into answerable questions for four sources of evidence (practitioners, research, organisational data and stakeholders), gather and judge what they find, and combine it into a proposal that other teams examine. The steps and the four sources come from the Center for Evidence-Based Management; the workshop format, published as 'Navigating Uncertainty', was designed by Wendelien van Eerde for the Transition Makers Toolbox.
Facilitation script
- 1
Case-giver presents the problem and the decision to be made. Clarifying questions from the group.
20 min - 2
Ask: teams of four formulate answerable questions, at least one per evidence source. Check each team's questions before they move on.
25 min - 3
Acquire: teams set a search approach for each source, divide the work, gather evidence and compare findings.
45 min - 4
Appraise: teams agree decision criteria and rate the trustworthiness and relevance of each piece of evidence.
25 min - 5
Aggregate: teams combine the evidence into a proposed decision with consequences for stakeholders and open uncertainties, and prepare a short presentation.
25 min - 6
Presentations and peer review: other teams question the gathering, appraisal and aggregation and score each proposal against the rubric.
30 min - 7
Case-giver responds. Plenary reflection on where proposals differ and what that says about the evidence.
10 min
Tips
Most of the quality is decided in the first step: a vague question produces a pile of loosely related material, so do not let teams start searching until each question names a specific outcome and context.
Insist that all four sources are used, because teams default to whichever is easiest to search.
Ask teams to state how confident they are in their proposal and what evidence would change their mind.
Common pitfalls
Starting to search before the questions are sharp. Teams collect whatever turns up and then build the proposal around it, which reverses the logic of the method
Relying on one source, usually a quick web search for research. The proposal ignores what practitioners and affected people know and fails on contact with the real setting
Treating all evidence as equal. A single blog post and a systematic review end up with the same weight, and the proposal is only as good as its weakest source
Searching for support for a preferred answer. The team presents a confident case and the peer review, if it is not rigorous, confirms a decision that was made before the session
Presenting the proposal as certain. Decision makers then stop monitoring the outcome, although evidence gathered in under an hour can only justify a provisional choice
Variations
Split format: run the case briefing and the Ask step in a first meeting, give teams several days to acquire evidence, including a few short interviews, and hold appraisal, aggregation and review in a second meeting. In-house version: for a real management decision, use internal data and interviews with affected colleagues as two of the sources and invite the decision owner as case-giver. Full cycle: the Center for Evidence-Based Management describes six steps; this format stops after four. Add the remaining two, applying the decision and assessing its outcome, as a follow-up review some weeks later. Online: teams work in breakout rooms with one shared document per team and present by screen share.
Where it fits
When to use it
A decision with real consequences is being driven by the strongest opinion or the most recent anecdote in the room
The team is about to adopt a practice because other organisations use it, and nobody has checked whether it works in a comparable context
Several kinds of evidence exist, such as research, internal figures and stakeholder views, and they have never been looked at together
You are developing managers or students who need to practise judging the quality of evidence, not only collecting it
A case-giver is available and you can give the work three uninterrupted hours with internet access
When not to use it
The options are already known and only need comparing against agreed criteria. A Decision Matrix does that in a fraction of the time
The decision is urgent and reversible. Decide, observe the result and adjust; a three-hour evidence process costs more than a wrong first attempt
The disagreement is about values or interests, not about facts. More evidence will not settle it; use a dialogue or consent-based format such as Consent Decision-Making
No one with first-hand knowledge of the case can attend. Teams then research an abstraction and the proposals do not fit the real situation
The group only needs to stress-test a plan that is already chosen. Run a Premortem instead
Related methods
Frequently asked questions
What is Evidence-Based Decision Making?▾
Evidence-Based Decision Making is a structured way for a team to reach a decision by deliberately gathering and weighing evidence from several sources instead of relying on opinion or habit. In the workshop format described here, teams work through four steps, ask, acquire, appraise and aggregate, and present a proposal that peers scrutinise. The approach comes from evidence-based management as described by the Center for Evidence-Based Management.
What are the four sources of evidence?▾
They are the professional experience of practitioners, findings from scientific research, data and facts from the organisation or local context, and the values and concerns of the stakeholders affected by the decision. The point of using all four is that each has blind spots. Research may not fit the local situation, internal data may be incomplete, and experience and stakeholder views can be biased.
How long does the process take?▾
The workshop format takes about three hours, which includes real search time. That is enough to produce a reasoned proposal and to practise the steps, but not for a thorough review of the research on a topic. For a consequential decision, spread the work over two meetings with several days in between for evidence gathering.
Does this cover the whole evidence-based management cycle?▾
No. The Center for Evidence-Based Management describes six steps; this format covers the first four and ends with a proposed decision. Applying the evidence in the decision and assessing the outcome afterwards are left out, so add a follow-up review if you use the method for a real decision.
How does the peer review work?▾
After each presentation, the other teams ask how the questions were chosen, where the evidence came from, how its quality was judged and how conflicting findings were combined. They then score the proposal against a rubric agreed in advance. The review looks at the quality of the reasoning, so a cautious proposal with well-appraised evidence should score higher than a bold one with weak support.
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Try it freeMethod descriptions on Workshop Weaver are original content written by our team, based on established facilitation practices. This method was inspired by work from Wendelien van Eerde, Transition Makers Toolbox; steps and evidence sources from the Center for Evidence-Based Management (CEBMa).