across this very broad literature there have been a range of methodologies used. while some see this as a weakness, others believe that the range of methodologies strengthens the argument in favour of HPWPs, because the findings have much in common, despite the different measures used. in looking at effect, some have used management perceptions, and some hard measures of performance derived from published data on compaines' results or stock market valuations. Some are studies of a single firm (eg Ichniowski's, 1990, study of a paper mill), some of industries (eg Berg et al.'s study of the appearel industry and Ichniowski et al.'s study of the steel industry), whilst others are cross sectoral (huselid, 1995; Ichniowski, 1990; Ichniowski and Shaw, 1995; Huselid and Becker, 2000 in Ichniowski et al. 2000; all in the US, and Wood S (1999) in UK