[en] This report provides guidelines for the data analysis necessary for the determination of the in situ thermomechanical response of basalt for the Full Scale 1 and 2 Heater Tests at the Near Surface Test Facility (NSTF). The effects of disruptive events, such as heater or instrument failure, on the system must be anticipated and appropriate plans formulated to minimize any long term changes. Techniques for the analysis of the data to determine the thermomechanical response of basalt are discussed which will allow spatial and directional variations of the material properties to be determined. The importance, at all stages, of relating the data to the observed rock characteristics is emphasized. 5 refs., 2 tabs