The aim of this paper is to suggest a new index-based methodology for more accurately measuring the convergence of governmental accounting standards with International Public Sector Accounting Standards (IPSAS) true and fair’s approach. The study focuses on the case of Switzerland by assessing the accounting standards established by the 26 cantons under two major reforms implemented between 1980 and 2018. Using the MACBETH multiple criteria decision analysis, we show that weighting index criteria to assess the convergence of homegrown accounting standards improves the measurement. However, this does not substantially change the conclusions drawn from the results obtained by the different cantons when index criteria are all considered to be equally important.