The sixth in this important series of articles by Stephen MacDonald on individual aspects of the assessment of uncertainty of measurement considers the impacts created when contributors are not measured in the same units. Coverage continues towards understanding the application of measurement uncertainty to laboratory assays.
The previous article (February 2018, page 27) ended by combining uncertainty contributors into an overall combined uncertainty; however, only contributors measured in the same units were considered. The next article, scheduled to appear in early April, will cover the effect of different units, will investigate whether it is possible to quantify the proportion of the overall uncertainty each contributes, and in doing so provide a mechanism to monitor and reduce uncertainty.