This paper reports on the on-going evaluation of a computer-assisted system (CEOTS) for the assessing of spoken English skills among Chinese university students. This system is being developed to deal with the negative backwash effects of the present system of assessment of speaking skills which is only available to a tiny minority. We present data from a survey of students at the developing institution (USTC), with follow-up interviews and further interviews with English language teachers, to gauge the reactions to the test and its impact on language learning. We identify the key issue as being one of validity, with a tension existing between construct and consequential validities of the existing system and of CEOTS. We argue that a computer-based system seems to offer the only solution to the negative backwash problem but the development of the technology required to meet current construct validity demands makes this a very long term prospect. We suggest that a compromise between the competing forms of validity must therefore be accepted, probably well before a computer-based system can deliver the level of interaction with the examinees that would emulate the present face-to-face mode.