Australia and New Zealand share a similar social and political history, and importantly, the rate of private health insurance coverage in Australia prior to the introduction of the PHIIS (30.1% coverage) was similar to the current rate seen in New Zealand (30% coverage) (Business Desk, 2012, May 23; Harley, Vaithianathan, Crossley & Cobb-Clark, 2002). The case selection technique is then in line with a ‘most similar’ case selection technique as presented by Seawright and Gerring (2008) which allows for the isolation of the variable of interest; the PHIIS.
Business Desk. (2012, May 23). NZ private health insurance uptake hits 6-yr low. The New Zealand Herald. Retrieved from http://www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=10807807
Harley, J., Vaithianathan, R., Crossley, T. F., Cobb-Clark, D. (2002). Parallel Private Health Insurance in Australia: A Cautionary Tale and Lessons for Canada. Retrieved from ftp://repec.iza.org/RePEc/Discussionpaper/dp515.pdf
Seawright, J., & Gerring, J. (2008). Case selection techniques in case study research: A menu of qualitative and quantitative options. Political Research Quarterly, 61(2), 294-308. doi:10.1177/1065912907313077