Abstract: An apparatus and method for determining the reliability of an electronic component by performing measurements which enable the ageing behavior of a parameter of that component to be predicted over time. The parameter measurements are made in-situ within the oven or environment used to control the temperature at which the measurements are made. The oven is controlled so that its temperature is kept stable, thereby permitting very high resolution measurements to be made over a relatively short time span. The temperature stability of the oven ensures that the changes of the electromagnetic parameter to be measured as a result of temperature fluctuations are negligible relative to the changes as a result of the ageing phenomena which occur in the component over time. The high resolution measurements are then used to model the parameter value as a function of time based on a deterministic model of how that parameter of the component varies over the lifetime of the component.