Kim Esbensen and Claas Wagner continue to stress that grab sampling is still an absolute no-no regardless of the size of the sampling device or the sample.
This column now turns its attention to sampling using a very popular tool, the “sampling spear”. There is much good to be said about spear sampling—and only one thing which is bad. But this is bad enough: spear samplers are very, very difficult to get to produce representative samples! The spear sampling principle can be made representative, but in most practical situations in which spear sampling is used today it manifestly is not. WHY? And more importantly, WHAT can be done about it? This column also turns out to touch on one of TOS’ six governing principles: SSI, Sampling Scale Invariance.