The paper presents an integrated approach to the problem of electrontemperature diagnostics of the plasma in a reversed field pinch. Threedifferent methods, sampling different portions of the electrondistribution function, are adopted, namely Thomson scattering,soft X-ray spectroscopy by pulse-height analysis and filtered softX-ray intensity ratio.A careful analysis of the different sources of systematic errors isperformed and a novel statistical approach is adopted to mutuallyvalidate the three independent measurements.A satisfactory agreement is obtained over a large range of experimentalconditions, indicating that in the plasma core the energy distributionfunction is well represented by a maxwellian.