Thermoelectric devices are a promising technology for reclaiming energy that would otherwise be lost as waste heat and converting it to usable electricity. A major hurdle to this goal is the limited performance of thermoelectric materials and the evaluation of new high performance materials. Determination of the constituent properties of the figure of merit ZTis generally done via separate measurements of the thermal conductivity, the electrical conductivity, and the Seebeck coefficient. Separate measurements of these properties not only slows down testing, but also allows more opportunity for error to be introduced when comparing different materials. As an alternative to separate measurement of the individual properties that comprise ZT, the properties can be simultaneously measured on the same sample. As all measurements are conducted simultaneously on the same sample, the test conditions for each property are truly identical ensuring the accuracy of the ZTcharacterization. Numerical simulations are used to investigate the impact of device design on measurement accuracy. Then, the device and methodology are validated using standard thermoelectric materials characterized using a high throughput testing apparatus. The testing rig is designed to allow rapid measurement of multiple samples at once. This design provides a platform for rapid, high accuracy characterization and comparison of materials.