A strongly recommended conclusion in sociology about trends in class inequality has been summarised by Goldthorpe as a high degree of 'temporal constancy and cross-national communality'. This conclusion, here called 'the stability thesis', was first challenged by Ringen in 1987 and again, on more methodological grounds, by Ringen and Hellevik in two papers published in 1997. These challenges resulted in a process of debate and reassessment. It is now possible to sum up and conclude. The stability thesis rests on empirical results from odds-ratio readings of mobility table data. The authority of this methodology is re-examined in terms of normative significance and statistical validity. Mobility table data which have generated stability thesis findings are reanalysed with the standard gini-index methodology in the study of inequality, then yielding different findings which contradict the stability thesis. The main conclusion is that the stability thesis can now be considered overturned. Keywords: social inequality, social justice, social reform, class analysis, social stratification.