• Types of Measurement Error

    We always want to avoid error, but it is a fact of life. At the foundation of analysis and modelling, we rely on measurements. Because errors in measurements are inescapable, the important question is how much does the error affect the result? I start the conversation by explaining what measurement error is, including its component parts, and what we can do to minimize its effect.

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  • Particle Size Analysis Toolpack v2

    A zip file containing a suite of tools for analyzing continuous particle size curves from laser diffractometry.

    Includes:

    • export templates for Malvern software,
    • analysis template for recommended quality control procedure,
    • reporting templates for organized presentation of results with additional metrics, and
    • a data filter for removing the larger particle size peak from bimodal curves.

     

    Download the PSA Toolpack (4.7 MB)
  • Accuracy vs Precision

    Scientists often measure and predict things. Therefore, we need ways to describe how much we know, how close a number is to reality, and how likely we are to get the same number again. The terms accuracy and precision are generally used to describe these things, but there can be some ambiguity. This post explains the difference between the two and explores the different aspects of precision’s multiple meanings.

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  • Precision of soil particle size results using laser diffractometry

    Because laser diffractometry produces much more detailed data than does traditional pipette analysis, and because a much smaller sample is used in the analysis, precision or repeatability of laser-produced PSA data is a concern. The approach presented provides both a simple method for assessing the variation in PSA data sets and establishes a comparable standard for determining when additional measurements are needed to find a more precise result.

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