Political trust is considered as a key factor related with social capital and democracy in any society (Offe 1995, Warren 1999, Hardin 1999, Uslaner 2009). The extent to which people trust their political institutions is one of the pillars of democracy and the decline of trust on institutions is one of the most evident and shared symptoms of the crisis, especially in those contexts where the crisis has been particularly acute. Political trust, or trust in institutions has been measured among European citizens by European Social Survey (ESS) during three time periods, 2008, 2010 and 2012 for 8 countries, namely, Germany, Netherlands, Sweden, Norway, Portugal, Spain, Greece and Ireland. Along this time frame, European societies have witnessed the presence and consequences of the crisis, affecting with different intensity and in different ways their views on the political system and political institutions.

We consider trust in institutions as a complex theoretical construct and will be treated as a latent variable. ESS data will be used to test whether the typical indicators for trust in institutions hold across periods and countries, affected differently by the crisis. Our expectation is that the levels of trust, as well as the composition of the latent variable, has experienced clear changes over time, as a consequence of the crisis. In addition to that, we also claim that the correlates impacting trust in institutions are significantly different among countries, depending on the degree in which they have been hit by the crisis. In this paper we will analyze to what extent trust in institutions can be comparable as a construct in different countries with significantly different levels of impact of crisis. In order to study its comparison, tests for measurement invariance of multiple groups and latent means will also be studied across time and countries. Both multiple group confirmatory factor analysis (MGCFA) and alignment method (AM) are analysed and the two are compared. The use of AM is especially relevant when a large number of groups exist. The invariance for alignment method allows for a substantial comparison of more groups than MGCFA, which is stricter.

 The main working hypotheses in this paper will be that the levels of political trust are expected to decrease significantly in those countries more affected by the crisis. Moreover, we expect significant differences in the effect of explanatory variables, due to unequal impact of the crisis in countries.