Press Release

ACGIH® Presents Industrial Hygiene Statistics and Bayesian Decision Analysis Workshop



Cincinnati, Ohio — May 19, 2008 — ACGIH® presents Industrial Hygiene Statistics and Bayesian Decision Analysis Workshop, a 2.5-day workshop that provides instruction on the basics of industrial hygiene statistics including censored data analysis, sampling strategy design, and Bayesian Decision Analysis. The workshop will be held October 6-8, 2008 at the ACGIH® Professional Learning Center in Cincinnati, Ohio. Earlybirds who register for the workshop on or before September 8, 2008 will save $100.00.

The application of Bayesian Decision Analysis to industrial hygiene decision-making is new and has been pioneered by the workshop instructor, Paul Hewett, founder and President of Exposure Assessment Solutions, Inc. Industrial hygienists, like all other professionals, routinely use professional judgment when making decisions. Bayesian Decision Analysis provides a mechanism for explicitly incorporating professional judgment into this decision-making process. The workshop will cover the application of Bayesian Decision Analysis to the analysis of gas/particulate data and noise data, relative to a traditional OEL, or in the European Union control banding and pharmaceutical control banding scenarios. The emphasis for this workshop is on attendees gaining an understanding of accurate "decision-making" using sound IH statistics and Bayesian Decision Analysis.

Day One – Industrial Hygiene Statistics and Censored Data Analysis

On the first day attendees are introduced to:

  • Normal and lognormal distributions
  • Event distributions (e.g., binomial distribution)
  • The calculation of upper percentiles (i.e., 90th, 95th, and 99th percentiles)
  • Exceedance fractions and confidence intervals
  • SEG exposure profile statistics (contrasted with OSHA inspector compliance statistics)
  • Censored data analysis (i.e., the analysis of datasets containing limit of detection values)
Day Two – Bayesian Decision Analysis

On the second day attendees are introduced to:

  • Bayesian Decision Analysis and calculations
  • Informative priors and parameter space
  • PPE selection
  • Noise exposure
  • EU Control Banding and pharmaceutical hazard classes
  • Integrating Bayesian Decision Analysis into industrial hygiene
  • Report writing
Day Three – Sample Size Estimation and Design of Performance-based Sampling Strategies

On the third day attendees are introduced to:

  • Principles of sample size estimation
  • Performance-based sampling strategies (i.e., a strategy where the probability of a false negative or false positive decision has been estimated for different exposure scenarios)
  • Design of baseline, surveillance, termination-reduction, and commissioning sampling strategies
At the end of this workshop, attendees will be able to:
  • Understand the statistical methods commonly used to describe occupational exposure data for gases, vapors, and particulates
  • Demonstrate the proper procedures for evaluating the goodness-of-fit for the lognormal distribution
  • Describe a dataset using an appropriate distributional model
  • Use an event distribution model for estimating the probability of observing an extreme event
  • Calculate upper percentiles (e.g., the 95th percentile) or the probability of exceeding an exposure limit or action limit
  • Calculate upper confidence limits and use them in hypothesis tests
  • Use censored data analysis methods to analyze and interpret a dataset containing measurements less than the minimally detectable concentration
  • Understand the principles behind sample size estimation and the design of a performance-based exposure assessment strategy
  • Understand the theory and assumptions that underlie Bayesian Decision Analysis
  • Use Bayesian Decision Analysis to classify exposure profiles
  • Use Bayesian Decision Analysis to assist in the selection of respiratory protection
  • Practice using Bayesian Decision Analysis to leverage "professional judgment" (using the "Initial Rating" and "Confidence Level" schemes)
The American Board of Industrial Hygiene has approved the workshop for 2.5 Certification Maintenance (CM) Points. The Board of Certified Safety Professionals has approved the workshop for 1.5 Continuance of Certification (COC) Points.

To register online for this workshop, visit the ACGIH® website at

ACGIH® is a member-based organization that advances occupational and environmental health. ACGIH® is one of the industry's leading publications resources, with approximately 400 titles relative to occupational and environmental health and safety, including the renowned TLVs® and BEIs®. For more information, visit the ACGIH® website at or call our Customer Service Representatives at 513-742-2020.

Amy Bloomhuff, Esq., CAE
Director of Operations