In the initial stages of testing new explosives, initiation methods, or mining and excavation methods, good planning of the work is only one of many requirements for success. It is also necessary to follow the different phases in the field operation when the methods are finally tested on a production scale. A large number of things can go wrong during the implementation of a field test and, when something malfunctions (which it sometimes does), it is tremendously difficult to draw the right conclusions from the results. There are numerous parameters to consider, and one should be sure to identify the parameter that has to be changed to eliminate the effect and consequences of a malfunction.