Experience and challenges of applying Bayesian methods in food safety risk assessments

Add to your list(s) Download to your calendar using vCal

• Dr. Marc Kennedy, The Food and Environment Research Agency (Fera), Risk and Numerical Sciences (RANS) team
• Tuesday 17 May 2011, 14:30-15:30
• Large Seminar Room, 1st Floor, Institute of Public Health, University Forvie Site, Robinson Way, Cambridge.

If you have a question about this talk, please contact Li Su.

The RANS team at Fera works with various government agencies, regulatory bodies and software developers in the UK and EU to try and develop and apply improved methods for probabilistic risk assessments across a range of policy areas. My work has been focused on quantifying uncertainty and variability within risk assessment for dietary exposure to pesticides. For risk managers it is clearly important to separate uncertainty from variability, so they can decide whether they should be collecting more data to reduce uncertainty or taking steps to reduce inherent variability by changing the system.

2-dimensional Monte Carlo (2DMC) algorithms have been used as the standard approach to separately represent uncertainty and variability, but these are frequently used incorrectly. Lognormal distributions are often assumed for the variability distribution as standard without justification. Also, many sources of uncertainty are ignored, or treated using ad-hoc methods. Problems include:

· Limited residue measurements from random market surveys

· Extremely high proportions of non-detects or missing residues

· Composite measurements from a small set of food units treated as a batch/field mean residue

· Measurement uncertainty of residues

· Limited dietary survey used to infer whole population eating habits (over a lifetime)

· Pesticide residues can come from multiple sources, e.g. a child might eat an apple and a pear on any given day, both of which were treated with pesticides

· Lognormal often fits badly, but what is the ‘right’ distribution?

I will talk about how Bayesian methods have been applied in a range of applications and list some open research problems. Computational aspects will also be mentioned.

This talk is part of the MRC Biostatistics Unit Seminars series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• BHRU Annual Lecture 2015
• BHRU Annual Lecture 2016
• Biology
• Cambridge Centre for Data-Driven Discovery (C2D3)
• Cambridge Immunology
• Cambridge talks
• Cardiovascular Epidemiology Unit Special Seminars
• Chris Davis' list
• Department of Public Health and Primary Care
• Graduate-Seminars
• Interested Talks
• Large Seminar Room, 1st Floor, Institute of Public Health, University Forvie Site, Robinson Way, Cambridge
• Life Sciences
• Life Sciences
• ME Seminar
• MRC Biostatistics Unit Seminars
• Primary Care
• PublicHealth@Cambridge
• Trust & Technology Initiative - interesting events
• bld31
• my_list
• ndk22's list
• ob366-ai4er
• other talks
• primary care
• rp587

Note that ex-directory lists are not shown.