One way to determine the kinetic parameters of a reaction with an associated loss in mass is by the production of a log plot viz. In[(d alpha/dt)/(fn(alpha))] = In A - E/(RT). The situation that arises when two or more reactions are occurring simultaneously is discussed. It is shown that the log plot can often help to elucidate that a complex reaction is proceeding, even when this is not obvious from the shape of the DTG curve. The influence on the shape of the log plot, when the activation energy E and/or the pre-exponential constant A varies either with temperature or extent of reaction, is discussed.