Posts

Journal papers and ideas I find interesting, explained for occupational hygienists. All credit to the original authors referenced within — I encourage you to read the source work.

Reflections
First Year of a PhD

A short self-reflection on the first 12 months of doing my PhD.

25 Jul 2026
Data Visualisation
The Best Worst Graph

Sometimes a chart is so messed up it’s almost beautiful.

19 Jul 2026
Bayesian methods
What’s a Prior?

An overview of priors in Bayesian data analysis, including a tool for exploring informative priors.

8 Feb 2026
Bayesian methods
Hierarchical Modelling

An introduction to hierarchical modelling, and the benefits of partial pooling over assessing data SEG-by-SEG.

27 Jan 2026
Statistics fundamentals
Why is my 95% UCL so high?

How the 95% UCL is driven by sample size and exposure variability.

9 Nov 2025
Statistics fundamentals
The Mean Caps Exceedance Fraction

A SEG’s arithmetic mean also tells you the maximum possible exceedance fraction. A little maths explains why.

23 Mar 2025
Exposure modelling
Task to TWA Estimation

Including the variability of each task-based sample gives far more information about the possible TWAs.

2 Mar 2025
Measurement
Gravimetric Uncertainty

Quantifying gravimetric analysis uncertainty under ISO 15767 and limits of detection.

2 Feb 2025
Standards & limits
Interpreting Workplace Exposure Limits

How exposure standards are written in legislation, and the questions raised by the new workplace exposure limits.

15 Dec 2024
Reflections
AIOH Conference ’24 Reflection

A short, personal reflection on the AIOH ’24 conference in Perth.

9 Dec 2024
Statistics fundamentals
Basic Hygiene Statistics

A basic overview of the statistics used in IHstats — less on calculation, more on the intuition of what they mean.

13 Oct 2024
Statistics fundamentals
Confidence Interval Fallacies

Clarifying common misconceptions about confidence intervals, and why Land’s exact approximation may be unreliable.

8 Oct 2024
Statistics fundamentals
What’s a UCL?

An explanation of upper confidence limits of the arithmetic mean.

21 Sep 2024
Statistics fundamentals
What’s an MVUE?

Exactly what an MVUE is, and how it compares to other ways of estimating the mean of lognormal data.

12 Jul 2024
Reflections
The Golems of Occupational Hygiene

Our systems and tools do exactly what they were designed to do — which isn’t always what the user intended.

26 May 2024
Book review
Quantitative Exposure Assessment

A review of Rappaport & Kupper’s hygiene-centric statistics textbook — challenging, but a genuinely interesting read.

18 May 2024
Statistics fundamentals
QQ Plots

A deeper look at how QQ plots are made, so you can get the most from them when checking your data’s distribution.

13 Apr 2024
Censored data
Substitution is Fabrication

There’s no consensus yet on treating censored data, but one thing is clear: substitution is fabrication.

6 Apr 2024
Bayesian methods
Markov Chain Monte Carlo

The algorithm that explores the parameter space of Bayesian calculations — the engine behind otherwise impossible solutions.

4 Mar 2024
Reflections
Reflection on ‘Worker Health First’

On the idealistic principles of occupational hygiene in tension with the priorities of business.

6 Feb 2024
Exposure modelling
Basic Exposure Modelling Tools

Estimating exposures without sampling — user-friendly modelling tools for preliminary assessment, with a note of caution.

26 Jan 2024
Bayesian methods
Bayes for Beginners

A feel for how Bayes’ theorem works, and why you should be using it in occupational hygiene.

5 Jan 2024
Reflections
Imposter Syndrome

A reflection on my experience at the 2023 AIOH conference.

8 Dec 2023
Reflections
Ethics of Real-Time Monitoring

What protections should be in place for the misuse of information collected during real-time monitoring exposure assessments?

24 Oct 2023
Exposure modelling
Robust Rule of Thumb: Quasi-Non-Parametric UTL

A more robust rule of thumb that allows you to compare the largest value with the OEL to determine compliance with high levels of certainty.

18 Oct 2023
Reflections
Transparency in Hygiene

How openly should we share the information we collect in exposure assessments? Are there limits? And what metrics should we use to tailor the communicated information to achieve the best outcome?

16 Oct 2023
Standards & limits
Complying with OSHA Control Tables

The OSHA silica table has been practically replicated in Queensland, Australia. Unfortunately, following the control requirements does not guarantee effective management of exposures.

28 Jul 2023
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Ethics of Real-Time Monitoring
John Padgham John Padgham

Ethics of Real-Time Monitoring

What protections should be in place for the misuse of information collected during real-time monitoring exposure assessments?

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