Any of the free eTools listed below can be used for accurately interpreting monitoring data. However, the Bayesian statistical tools (IHDA-AIHA and Expostats) offer significant advantages over the traditional statistical tools (IHSTATTM), particularly for analyzing censored data (non-detect values below the limit of detection) and for communicating the results of the analysis.

Note that the IT departments in some organizations restrict employees’ ability to install software or run macros in Excel, so give yourself plenty of time to work with them to get the software installed, where necessary. The primary version of Expostats runs on a web-based server and therefore requires no installation. This might be the best choice for someone using a work PC with very strict administrative restrictions on the software that can be installed.

IH e-Tools

  • IHDA-AIHA is a free version of the IH Data Analyst program ( designed for EHS students and professionals taking classes or professional development courses on the analysis and interpretation of occupational exposure measurements. The program calculates the standard descriptive and decision statistics recommended by the AIHA and includes goodness-of-fit procedures and graphs, several methods for analyzing datasets containing non-detects, and Bayesian Decision Charts, which were designed to assist in the selection of the most appropriate AIHA exposure control category. IHDA-AIHA must be downloaded and installed on a Window-based PC. It will not run on a Macintosh computer without an emulator.
  • Expostats is a free toolbox of web applications from the University of Montréal for the interpretation of industrial hygiene measurements using the lognormal distribution. Tool1, 2, and 3 from Expostats answer the following questions, respectively: is my similar exposure group overexposed? Is my similar exposure group homogenous? What factors are associated with exposure levels in my dataset? All calculations are performed using Bayesian statistics and results are presented in the intuitive probabilistic form. An offline version is also available
  • IHSTATTM is an Excel application that calculates various exposure statistics, performs goodness of fit tests, and graphs exposure data. Multiple languages are available.
    • IHSTATTM (macro-free version) is an Excel spreadsheet without macros that require that Excel be installed on your PC.
    • IHSTATTM (multi-language version) (latest version: 0.238, February 2019) is an Excel spreadsheet with macros that requires that Excel be installed on your PC and that the use of macros has been enabled.
  • The links below will show you how to adjust the macros settings in your version of Excel if needed.


  • The book “A Strategy for Assessing and Managing Occupational Exposures” is intended to accompany the use of these tools. It provides critical detail on the use and interpretation of the various statistical outputs. To purchase the book visit the AIHA Marketplace ($99 AIHA member/$130 non-member).