Sampling Strategy Design and Sample Size Estimation

Location – (Web PDC)

Instructions regarding how to log onto the web PDC and the conference call phone number, as well as handouts, will emailed to the registered participants the week before the PDC.


Dr. Paul Hewett Ph.D.

Course Description

This web PDC introduces the participant to the design of performance-based exposure assessment strategies, as well as an introduction to sample size estimation. The focus will be on designing strategies that will reliably determine if the exposure profile for a worker or similar exposure group (SEG) is acceptable or unacceptable, relative to a full-shift, TWA occupational exposure limit. (See the list of Prerequisites.)

The PDC will last 3.0 hours, with an additional 30 minutes for Q&A.  Each participant will receive a certificate confirming participation in the PDC.

Learning Objectives

  • Principles of exposure assessment hypothesis testing.
  • Principles and steps for designing a performance-based strategy.
  • Experience using freeware software for generating performance-curves.
  • Experience designing a baseline and a surveillance sampling strategy.
  • Rule-of-thumb for estimating sample sizes.
  • Parametric and non-parametric calculation methods for estimating a reasonable sample size.


  • Participation in the webinar PDC “IH Statistics and Decision Making” or a strong background in IH statistics
  • Familiarity with the AIHA Exposure Assessment and Management Model (see the AIHA monograph “A Strategy for Assessing and Managing Occupational Exposures”, 4rd Edition (2015)
  • Recommended reading prior to the WebPDC:
    • Hewett, P. (2005): Technical Report 05–03 – Performance-based exposure assessment strategies for TWA exposure limits. Exposure Assessment Solutions, Inc. (available free from

Presentation List

  • Definitions, Assumptions, and Goals
  • Principles of Hypothesis Testing
  • Minimizing False Negatives and False Positives
  • Exposure Assessment Issues and Pitfalls
  • Designing a Performance-based Exposure Assessment Strategy
  • Statistics-based vs. Rule-based Sampling Strategies
  • Introduction to the Exposure Assessment Strategy Simulator Program (EASS)
  • Workshop – Use EASS to Critique a Company Strategy
  • Rules-of-thumb for Estimating Sampling Sizes
  • Formulas for Estimating Sample Sizes + Workshop
  • Issues and Controversies in Exposure Assessment
  • Q&A


See Registration page.

Cancellation Policy

See Registration page.

Read these notes before you sign up:

NOTE: The registration and participation policy for each Web PDC is the same as for a fixed location or on-site PDC. Each particpant must register. Registration is per participant, not per viewing site. Only those registered should view and particpant in this web PDC.

NOTE: The email address submitted at the time of payment will be used for all email communications and for logging onto the web PDC.

NOTE: This web PDC will presented using GoToMeeting. GoToMeeting must be installed on your computer. To install (usually takes less than two minutes), click on the GoToMeeting link above, scroll to the bottom of the page, and click on the link “Download GoToMeeting (for customers)”. If you do not have adminstrative privileges for your computer have your IT person install the GoToMeeting software well in advance of the web PDC.

NOTE: The conference call number will not be toll free. You will be responsible for any long distance phone charges if you do not have an unlimited long distance account. However, you may also connect using your computer speakers and microphone or headset (VoIP).

NOTE: See the “Prerequisites” below for software and freeware that will be helpful when taking this web PDC. To download and install the program(s) you must first be a registered member of