This question is inspired by two papers I encountered, which came to the same conclusion using different sources to quantify the ideological distance between political parties in various countries: one used public opinion surveys and the other used the Encyclopedia Britannica's description of the party's ideology. (Both papers used a simple, unidimensional Left-Right ideological scale.)
What I want to ask here is: is there usually an agreement (this can be quantified e.g. as inter-rater agreement) between expert assements of party's ideology and public perception of said ideology? Or is there generally an agreement (between experts and public opinion) at least on the ideological distance between parties?