Worker involvement in decision-making about the workplace can improve safety, health, productivity and the quality of organizational outputs. Australian work health and safety (WHS) legislation mandates worker involvement and gives elected Health and Safety Representatives (HSRs) specific powers, but there has been limited research about the impact of that regulatory framework on the nature, quality and outcomes of worker involvement. As part of a wider review of worker representation in WHS, we investigated the role and impact (positive and negative) of elected HSRs on WHS] in South Australia using a newly-constructed survey instrument. This paper reports on the development of the instrument and the initial findings of the research. The initial survey dimensions and items were developed from earlier research on consultation in South Australia and were refined and validated through this research. The survey has 9 constructs and 61 items and has both face validity and high internal consistency. This research is a step forward for researchers and policy makers seeking a means of determining the effectiveness of worker participation in WHS. It provides an instrument, pilot baseline data and a method that could be used internationally to enable this assessment.