This paper describes a theoretical framework, based on real-time analysis of the shape of thermoanalytical peaks, for two new approaches to sample controlled thermal analysis (SCTA). These new methods have the common aim of effecting changes in the heating rate at a given point in a process (i.e. at a set value of α) irrespective of the absolute magnitude of the peaks produced by that process. This permits the automatic on-line optimisation of the resolution/experiment time ratio without the need for preliminary experiments. (C) 2000 Elsevier Science B.V.