PhilPharm at British Society for the Philosophy of Science’s annual meeting

Posted on

13.07. – 14.07.2017: Barbara Osimani and Juergen Landes presented in Edinburgh. Barbara Osimani gave a talk entitled “Exact replication or varied evidence? Reliability, robustness and the reproducibility problem”. Juergen Landes presented on “Variety of Evidence”.

Jürgen Landes visiting George Masterton

Posted on

One key challenge in medical inference are the enormous sums at stake and the hence inherent vested interests. The reliability of all items of available evidence is hence to be carefully assessed. Intuitively, the greater the variety of sources and kinds of evidence which points in the same direction, the higher the assessed reliability and thus stronger the evidence confirms a hypothesis, ceteris paribus. This intuitive thought is known as Variety of Evidence Thesis.

Previous work (Bovens and Hartmann, Bayesian Epistemology. Oxford University Press, 2003, Claveau 2013) on this thesis reports surprising failures in which the less diverse body of evidence for a hypothesis confirms the hypothesis more strongly than the more diverse body of evidence. Barbara Osimani and I have developed a framework for the formal evaluation of the Variety of Evidence Thesis under more realistic modelling assumptions regarding the reliability of scientific instruments which are closer to statistical practise. The upshot is that the Variety of Evidence Thesis fails mostly for borderline or counter-intuitive cases and holds otherwise. However, when reliability is modelled exogenously, then the Variety of Evidence Thesis does hold and it can be given a formal Bayesian justification, as I show in an  — as of yet — unpublished manuscript.

These papers are embedded in an overarching framework aiming to provide a formal analysis of statistical inference, see Landes et al. 2017. The aim here is twofold: on a more theoretical level, formal epistemology should provide a sort of lingua franca, where different conceptualisations of error and different statistical techniques can be discussed and investigated; on a more practical level, we aim to use formal epistemology as a framework for the incorporation of various evidential dimensions in the overall assessment of investigated hypotheses.

Within this greater projected I visited George Masterton — based at Lund university — who is an expert in judgement aggregation and the philosophy of science. He is involved in the application of Laputa which is a research tool and a sandbox environment for simulating the attainment of knowledge in social networks, see (Masterton2013, Masterton 2014). Having successfully cooperated (Landes & Masterton 2017), I visited George Masterton in Lund to apply Laputa to the problem of modelling reliability of evidence in medical inference and how different concepts of the notion of reliability influence rational — Bayesian — beliefs in a social world.

Work on a jointly-authored manuscript has begun. Barbara Osimani has kindly agreed to participate in the joint effort. We are looking forward to joyful and labor-intensive period of readings, discussions and writing.

Jürgen Landes

PhilPharm at Mechanisms in Medicine

Posted on

Presentations at the Mechanisms in Medicine Conference 2017

03.07. – 05.07.2017: Juergen Landes and Roland Poellinger presented in Canterbury. Juergen Landes presented on “Mechanisms, drug safety and varied evidence”, and Roland Poellinger gave a talk on the PhilPharm core ideas and challenges with his presentation on “Probabilistic Causal Inference from Heterogeneous Evidence”.

Review of `Lectures on inductive logic’ published

Posted on

Juergen Landes published a short review of a monograph on the phiolosophy of inductive inference.

PhilPharm at NNPS 2017

Posted on Updated on

Presentation at the Nordic Network for the Philosophy of Science 2017

20.04. & 21.04.2017: Juergen Landes and Roland Poellinger presented in Copenhagen. Juergen Landes presented on “Exact Replication or Varied Evidence?”, and Roland Poellinger gave a talk on the PhilPharm core ideas and challenges with his presentation on “Probabilistic Causal Inference through Evidence Amalgamation”.

Workshop Report on Drug Safety, Probabilistic Causal Assessment, and Evidence Synthesis

Posted on Updated on

On 27-28 January 2017, the workshop Drug Safety, Probabilistic Causal Assessment, and Evidence Synthesis took place at the LMU in Munich organised by Bennett Holman, Jürgen Landes, Barbara Osimani, Roland Poellinger and David Teira. The goal of the workshop was simple, yet ambitious: to provide a platform for scholars of various disciplines and decision makers to meet and discuss issues of causal assessment in drug safety.

In confronting such a multifaceted topic, relying on just one perspective is inadvisable, if not outright dangerous. Therefore a closer collaboration between experts of different fields and regulators is pivotal for improving our policies and our answers to crucial questions in pharmaceutical risk assessment. 21 presentations from speakers based in Australia, Austria, Germany, Great Britain, Italy, Luxembourg, the Netherlands, Norway, South Korea, Spain and Sweden o ered perspectives from a wide variety of angles. Such a broad perspective is especially important for philosophers involved in a research program which strives to develop a variety of tools to address methodological and epistemological issues in causal assessment in medicine, since such a program requires the interaction with, and thus knowledge of, the work of health professionals, methodologists, statisticians and epidemiologists. It also provided non-philosophers an opportunity to learn more about current philosophical work.

Barbara Osimani (MCMP/LMU) presented an inferential framework for the purpose of probabilistic causal assessment, which she is developing together with Jürgen Landes (MCMP/LMU) and Roland Poellinger (MCMP/LMU) within the ERC project: Philosophy of Pharmacology: Safety, Statistical Standards, and Evidence Amalgamation. This consists in a Bayesian network specically adapted to model epistemic dynamics in probabilistic causal assessment that blends together different perspectives that in standard Evidence Based Medicine are working relatively independently so far. Roland Poellinger further elaborated on the concept of exploiting a Bayesian evidence amalgamation framework to formally explore the interplay between heterogeneous evidence and the different components of a causal hypothesis in pharmacological risk assessment. Jürgen Landes strengthened the case for the Variety of Evidence thesis (the thesis that more varied evidence speaking in favour of a hypothesis confirms it more strongly than less varied evidence, ceteris paribus).

The CauseHealth project contributed two presentations: Rani Lill Anjum (Norwegian University of Life Sciences) and Elena Rocca (Norwegian University of Life Sciences) suggested an integrated framework in which post market monitoring, through the study of treatment failure, feeds pre-clinical and clinical research with mechanistic hypothesis, while Stephen Mumford (University of Nottingham) presented suggestive points in support of a dispositionalist stance regarding understanding of probability and synthesis of evidence. The EBM+ consortium, which seeks to make the role of evidence of mechanisms in the evidence appraisal process more explicit was introduced by Jon Williamson (University of Kent), who spoke about two research project related to evidence of mechanisms. For the Making Scientific Inferences More Objective project Felipe Romero (University of Tilburg) presented approaches in finding a middle ground in the current reform efforts to increase replicability in sciences.

Jeff Aronson (Oxford University) gave great insight on a crucial aspect of any discussion about causality in medicine and pharmacology, namely the definition of what a signal is. Ralph Edwards (Uppsala Monitoring Center, WHO) presented on the problem of discovering causality in pharmacovigilance from real-world data.

David Teira (UNED Madrid) argued that the shift toward evidential pluralism undergoing in regulatory agencies (at least in the U.S.A.) involves a de facto relaxation of regulatory paternalism, while Bennett Holman (Yonsei University) spoke on the problematic and unavoidable deep connection that runs between industry and science and how the former shapes the latter by means more subtle than one might expect.

Regarding the hot debate that is going on over Randomized Controlled Trials and its reputation as being the cornerstone of Evidence Based Medicine, Mike Kelly (Cambridge University) presented an alternative narration in form of the Medicines Adaptive Pathways to Patients, while Ulrich Mannsmann (IBE/LMU Munich) provided a detailed analysis on how to quantify the effect of and correct design-dependent bias in RCTs. Stephen Senn (CCMS, Luxembourg Institute of Health) addressed the benefits and limits of randomization in technical research and covered some fallacious critical arguments against RCTs. Adam La Caze (University of Queensland) examined three different approaches to amalgamating drug safety evidence, pointing out that there is still room for conceptual refinement. Jacob Stegenga (Cambridge University) defended a middle view between the claim that causal inference in medicine should be based on statistical evidence and the one that identify the focus in mechanistic evidence, showing how reasoning about causal relations by appealing to both is vindicated by our best general
theory of inference.

Martin Posch (Medical University of Vienna) underlined the challenges that decision makers have to face in data interpretation, in which a balance between a qualitative and a
quantitative approach have to be reached.

Last but not the least there were the voices of the regulators and decision makers themselves, who provided invaluable insight on the mechanics and the reasoning behind the everyday decision-making processes in pharmacovigilance, which in itself was of tremendous interest to all participants. Norbert Benda (Bundesinstitut für Arzneimittel und Medizinprodukte) discussed some principles for a decision-theoretic framework in drug safety and benefit risk assessments, the related challenges and consequences and contrasted Bayesian and frequentist reasoning in risk assessment. Brigitte Keller-Stanislawski (Paul Ehrlich Institut and PRAC) discussed aspects of the European Union regulatory approach for benefit risk assessment post-authorization and gave an overview of the legal framework for decision making in the EU. Beth Shaw (NICE) outlined the use of
heterogeneous knowledge in guideline development and some challenges and potential solutions with this approach, focusing in particular on possible alternatives to Randomized Controlled Trials.

For the first time, an event brought philosophers, statisticians and decision makers together to discuss drug safety. The lively discussions throughout the workshop covered a wide range of issues which are ongoing and continue to deepen our understanding. Together we shall face arising challenges in drug safety by drawing on the expertise of researchers with a great variety of backgrounds.

— Report by  Alessandro Demichelis

Smile of the day

Posted on Updated on

Did you ever wonder about p-values? If so, this list might cheer you up.