Before revision:  We define a multi-valued characterization of political attitudes towards migrants and we assume that the extent to which each country can be influenced by another  is modeled by an appropriate indicator, that we call Interference Compound Index (ICI) . Results suggest that implementing  highly restrictive immigration policies leads to an increase of crime rates and the magnitude of estimated effects is stronger if we take into account multi-valued interference .
After revision:  We define a multi-valued characterization of political attitudes towards migrants and we assume that the extent to which each country can be influenced by another is modeled by an appropriate indicator, summarizing their cultural and geographical proximity . Results suggest that implementing highly restrictive immigration policies leads to an increase of crime rates and the magnitude of estimated effects is stronger if we take into account multi-valued interference .