There is an increasing number of small-scale dynamic plate test devices available which reportedly measure an elastic stiflhess modulus for the foundation material under test. They exhibit many similarities in the mechanics of operation although there are many subtle differences in mode of operation, transducers utilised and analysis procedure, which lead to variations in the measured results. Three such devices are reviewed in some detail in this paper. Findings from a laboratory investigation of dynamic plate test mechanics are presented which highlight the important role of inertia, both for the device and the soil. Field derived data are then presented which demonstrate the comparative performance of two devices to the FWD and these are then discussed in light of the laboratory findings. Conclusions are then drawn and recommendations made for the key functional requirements of such tests.