【摘要】This paper presents a detailed definition of mode 4 in the GATS framework, identifies the specific information necessary for discussing mode 4 in the GATS context, set out the ways in which some of this information may be eventually derived from established statistical systems.Finally, it uses the national accounts framework and in particular the SAM which is linked to labor matrices (in volume and prices) for the measurement of the movement of natural persons-Mode 4.