Maintaining a common unit in social measurement

Acknowledgements The paper is based on the author’s Ph.D. thesis completed at Murdoch University, Western Australia, with Prof David Andrich principal supervisor and Assoc Prof Guanzhong Luo co-supervisor. The author wishes to acknowledge the extensive input and assistance of David Andrich in shaping the final draft of the manuscript, as well as his guidance, input and vision throughout the process of undertaking the research. Permission by the Department of Education & Training, Western Australia is acknowledged for the use of the empirical data featured within the paper. Support within the Department has also greatly benefited the research. The work for the Report was supported in part by an Australian Research Council grant with the Australian National Ministerial Council on Employment, Education, Training and Youth Affairs (MCEETYA) Performance Measurement and Reporting Task Force, UNESCO’s International Institute for Educational Planning (IEP), and the Australian Council for Educational Research (ACER) as Industry Partners*.