Bayesian talk on how to use computers to analyse data – REACH Meeting

Ullrika gave a talk on Bayesian Inference at the upcoming REACH  Discussion Meeting on 27 October in Lund

Link to the talk and some files are here:

My talk followed directly after a talk about Machine Learning which is a very nice

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Quantifying uncertainty integrating expert judgement and data – tutorial

Ullrika travelled all the way to Liverpool to give a tutorial at the BayesDays. Nice event.

The material for the tutorial in on github:

A Bayesian model? !

Pizza for lunch to keep pace with the talks

The room for the BayesDays with people – not sitting an listening?

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Trusting expert judgments – seminar Oct 25th 2017

Welcome to a seminar on the book Trusting Judgments


The seminar was led by the participants and gently facilitated by Ullrika. We went go through the book chapter by chapter. It was a very useful and inspiring day. Thank you all for coming. The old Bishop house in Lund is an excellent place for smaller workshops.

This is a seminar supported by the strategic research environment BECC and arranged by the BECC action group “Evidence relying on simulation models and expert judgment”


Why this book

This book is intended for people in government, regulatory agencies and business who routinely make decisions and who rely on scientific and technical expertise. So-called evidence-based decision-making has become more popular over the last decade, but often the evidence we need for these decisions is unavailable. Time, money and the pressing nature of many decisions prevent us from collecting much of the information we need. In its place, decision-makers turn to experts to estimate facts or make predictions. The status of scientific and technical experts has evolved over the last 100 years or more to provide unprecedented opportunities for experts to influence decisions. The hidden risk is that scientists and other experts overreach, often with good intentions, placing more weight on the evidence they provide than is warranted. The tendency to overreach is pervasive and more significant than many scientists and decision-makers like to admit. Much of the evidence for these phenomena is drawn from well-established research on decision theory and cognitive psychology. This book documents the extent and importance of this issue, and then outlines a suite of simple, practical tools that will assist decision-makers to make better use of expert estimates and predictions. It provides the means to discriminate good advice from poor, and to help decision-makers to be reasonably and appropriately skeptical. The book promotes a change in attitude towards expert predictions and estimates such that they are treated with the same reverence as data, subjected to the same kinds of cross-examination and verification. By requiring a little discipline from their experts, decision-makers can avoid the most pervasive pitfalls of expert judgements and assure themselves of relatively reliable and accurate expert information.

The author of the book

Mark Burgman is Director of the Centre for Environmental Policy at Imperial College London and Editor-in-Chief of the journal Conservation Biology.  Previously, he was Adrienne Clarke Chair of Botany at the University of Melbourne, Australia. He works on expert judgement, ecological modelling, conservation biology and risk assessment.  He has written models for biosecurity, medicine regulation, marine fisheries, forestry, irrigation, electrical power utilities, mining, and national park planning.

The book

Trusting Judgements: How to Get the Best out of Experts by Mark Burgman. Cambridge: Cambridge University Press. 2015. doi:10.1017/CBO9781316282472

Ch1. What’s wrong with consulting experts?

Ch2. Kinds of uncertainty

Ch 3. What leads experts astray?

Ch 4. Dealing with individual experts

Ch 5. The wisdom of crowds revisited

Ch 6. Tips to get the best out of experts


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Gaming for better decision making – one winner at Climate-Kic Nordic Ideation Day

The project Gaming for better decision making was one of the winners at the Climate-Kic Nordic Ideation Day in Aarhus August 23 2017.

Ullrika recieves the award from the Climate-Kic community.

Ullrika was there pitching it in front of a jury. Great day with a lot of positive feedback and useful connections.

Gaming for better decisions under uncertainty is a project with the aim to develop a computer game that motivates people to learn about uncertainty analysis and decision making in an entertaining way. The game will explain the benefits of expressing uncertainty when making predictions and possible ways to make decisions under uncertainty.

Extraction of the poster used at the Ideation Day.

The game will include prediction and decision problems from daily life that players can relate to, and a fictional game scenario that involves decision making under climate uncertainty, where there is a need to consider the balance between social, economic, and environmental impacts. A case-study on climate decisions under uncertainty will be developed on flood protection in the municipality of Vejle, Denmark. We will benefit from previous experience in serious gaming at Aarhus University.

By the end of 2017 we will have an operational game prototype.

The game is expected to result in

– a greater interest to learn more about uncertainty among experts and decision makers

– a wider use of subjective probability for uncertainty

– a tool to initiate discussions on how to adapt uncertainty analysis to your decision problem

Partners: Lund University, DTU, Aarhus University, Vejle municipality

People (to be updated):

Ullrika Sahlin, Associate Professor, Lund University, Sweden. Uncertainty analysis in risk and environmental impact assessment.

Anthony O’Hagan Emeritus Professor, the University of Sheffield, UK. Eliciting expert knowledge using subjective probability; e-learning to train experts to express uncertainty accurately and rigorously.

Igor Linkov, Adjunct Professor, Carnegie Mellon University. Expert on decision making with applications on climate adaption and development of serious games of decision making.

Igor Kozine, Senior Researcher and Miroslava Tegeltija, PhD Student. Technical University of Denmark (Danmarks Tekniske Universitet). Quantitative and semi-quantitative approaches to uncertainty representation.

Matthias C. M. Troffaes. Expert on decision making under uncertainty with imprecise probability; applications in engineering and environmental sciences; avid gamer. Associate Professor (Reader), Durham University, UK.

External reviewer:

EFSA, Assessment and Methodological Support Unit, Olaf Mosbach-Schulz. Implementing uncertainty analysis in food and feed risk assessment. Training programs on probabilistic judgements for external experts.

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The 3rd Nordic Chapter Risk conference in Finland – Call for abstracts

The Nordic Chapter of the Society for Risk Analysis (SRA) invites abstracts to the 3rd conference which will be held at Aalto University, Espoo, Finland, November 2-3, 2017. (20 minutes’ bus trip from Helsinki).

The theme of the conference “Risk and Security” highlights the role risk plays in relation to security.

If you attend this conference you can listen to talks on risk and security from different disciplinary perspectives covering maths to social science

See more on the conference web

Register before October 17th



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The Bayes@ concept

Bayes@: Approachable mini conferences on applied Bayesian statistics

A Bayes@ mini-conference is a (more or less) local one day event bring together people working with or interested in Bayesian methods. Bayes@ events aims at being accessible to people with little experience of Bayesian methods while still being relevant to experienced practitioners. The focus is on how Bayesian methods are used in research and industry, what the advantages and challenges are with using Bayesian methods, and how Bayesian methods can be used and taught in a better way.

The first Bayes@ event was organized in Lund, Sweden by Rasmus Bååth and Ullrika Sahlin in 2014 when they noticed that, while many people use Bayesian methods at the university, they were spread all over campus. Rasmus and Ullrika thought: Why not meet up and share experiences and tips in a one day mini-conference? And so they did.

Read more on the github page

Contact Ullrika or Rasmus if you are interested in arranging a Bayes@ conference. Have fun : )

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Extreme events in the real world and in the mind

My sister caught me in the act explaining different types of uncertainty

Last Friday April 28th I gave my docenture lecture for Environmental Science at Lund University. I talked about the importance of considering extreme and rare events in environmental management. It was fun. Thanks all for coming. My presentation is here

Abstract: Have you ever missed a train or got stunned by a surprise you did not expect to happen? In retrospect, could you have done something to prevent bad things from happening and still get the good bits? These questions are valid, not only for our daily decisions, but also for decisions on how to manage the natural environment for conservation, safety or sustainability. To help out, there are theories for considering the extreme, rare or unlikely in decision making, with applications to the management of environmental systems.

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Lundaloppet predictive challenge 2017

Forecasting with uncertainty

Guess your time in Lundaloppet 2017 and express your uncertainty in your running time in which way you want!

After the race on May 13th in Lund and the actual running times are known, we will evaluate the performances of all predictions. The results will be presented in June, where we will hand out several awards.

Make your forecast here 25 people have guessed their running time. Thank you all for participating. 

The challenge is open for anyone

The purposes with the challenge are to highlight what it means to forecast with uncertainty and collect examples of how people prefer to express uncertainty. Any way to express uncertainty is allowed, ranging from qualitative to quantitative, using probabilistic and non-probabilistic descriptions.

The participants are asked to guess their own running time and are therefore basing the forecast on best available (expert’s) knowledge. The nature of the question force them to think about uncertainty as their own, which demonstrate the subjective nature of uncertainty. Finally, participants are asked to rate their confidence in their forecasts, which is a more frequently occurring way to judge strength in predictive knowledge.  

The Lundaloppet predictive challenge was previously been given 2014 with great success.

This challenge is organized by the research group UnEviL (Uncertainty and Evidence Lab) at the Centre of Environmental and Climate research and is an activity of the BECC action group: Evidence relying on simulation models and expert judgment.

For more info contact

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The dawn of the new research group “UnEviL”

Uncertainty and Evidence Lab is the name of a new research group at Lund University. The group is led by Ullrika Sahlin at the Centre of Environmental and Climate Research.

Can we trust what we see or believe?

This research group focus on the management of uncertainty and evidence in risk analysis, evidence synthesis, decision analysis and, never the least, predictive sciences. This include discussing and applying principles and methods for learning, forecasting and decision analysis under different strengths in knowledge. We seek to apply the principles and methods on conceptual and actual problems and we are not limited to a specific application.

The research group, ongoing activities and output are presented at Lund University research portal

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Bayes@Lund2017 20th April

The program for Bayes@Lund2017 is now ready

Follow us at #bayeslund17 on twitter

We have uploaded videos of some of the talks on YouTube. Unfortunately not all talks have been recorded because of technical issues.

Richard McElreath — Bayesian Statistics without Frequentist Language:
Martin Stjernman — Joint species modelling. Beautiful in theory, tricky in practice:
Shravan Vasishth — Finite mixture modeling: a case study involving retrieval processes in sentence comprehension:
Mark Andrews –Teaching Bayesian methods to social scientists:
Stefan Wiens — Making the most of your ANOVAs: From NHST to Bayesian analyses:
Judith Bütepage — Learning to make decisions under uncertainty:

Ullrika Sahlin — Using expert’s knowledge in Bayesian analysis: link to presentation no video unfortunately Sahlin_BayesatLund2017

We start in room MA4, Maths building Annex, Sölvegatan 20. We also have a booklet of the abstracts programBayes@Lund2017 maps and tips.

[for the tutorial on 19 April go here]

08.30-9.00 Registration

09.00-9.10 Welcome and an overview of Bayesian activities in Lund: Umberto Picchini and Ullrika Sahlin

9.10-10.05 Keynote talk Darren Wilkinson: Hierarchical modelling of genetic interaction in budding yeast

10.05-10.30 coffee break

Bayesian Analysis I

10.30-10.55 Stefan Wiens, Making the most of your ANOVAs: From NHST to Bayesian analyses

10.55-11.20 Martin Stjernman, Joint species modelling — beautiful in theory, tricky in practice

11.20-11.45 Shravan Vasishth, Finite mixture modeling: a case study involving retrieval processes in sentence comprehension

11.45-13.05 Lunch break  

13.05-14.00 Keynote talk Richard McElreath: Understanding Bayesian statistics without frequentist language

Decisions and Teaching

14.00-14.25 Judith Butepage: Learning to make decisions under uncertainty

14.25-14.50 Mark Andrews: Teaching Bayesian Data Analysis to Social Scientists

14.50-15.10 coffee break

Parallel Sessions

Bayesian Analysis II (room MA7)

15.10-15.35 Thomas Hamelrick: Potentials of mean force for protein structure prediction: from hack to math

15.35-16.00 Junpeng Lao: Statistical Inferences of Eye movement data using Bayesian smoothing

Teaching Bayes (room MA6)

15.10-15.35 Richard Torkar: Convincing researchers to transition to Bayesian statistics – the case of software engineering

15.35-16.00 Bertil Wegmann: Experiences from teaching Bayesian inference to students familiar with frequentist statistics

all back in room MA7 for the final session

Bayesian Analysis III (room MA7)

16.05-16.30 Erik Lindström: Multilevel Monte Carlo methods for inference in multivariate diffusions

16.30-16.55 Ullrika Sahlin: Using expert’s knowledge in Bayesian analysis

Funding from the research schools BECC and COMPUTE is greatly appreciated

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