There is an element of truth to the maxim that "a measurement presented without a specified uncertainty level is a lie". It is common - but misleading - practice to suggest a high level of precision by including many places after the decimal point. Meanwhile, two different readings of the same quantity may indeed be correct, despite the measured values differing.
An indication of uncertainty based on the ISO/IEC "Guide to the Expression of Uncertainty in Measurement" (GUM) is required in DIN EN and DIN IEC standards for radiation protection dosimeters and similar instruments. The purpose of the new VDE Guideline is to support the use of the GUM. The principle of the GUM is first presented using a very simple but concrete case; numerous examples are then given in five annexes.
Each annex focuses on a particular type of measuring device. The first example of each annex gives the total measurement uncertainty of a measuring device which meets all the minimum requirements of the product standard. The second example determines the uncertainty level based on additional information in a specific measurement.
The VDE Guideline developed by the "Radiation Protection Dosimeter" committee contains two methods for determining the uncertainty, concrete information on the situations in which the two methods should be used, and finally a very simple method for deciding whether a measurement result is negligible or not.