This is the replication material for Carvalho, J. and Ruedin, D. 2018. ‘The Positions Mainstream Left Parties Adopt on Immigration: A Crosscutting Cleavage?’, *Party Politics*. Forthcoming. doi:10.1177/1354068818780533 The article is available here: http://journals.sagepub.com/doi/full/10.1177/1354068818780533 The post-print is available on an institutional repository: https://libra.unine.ch/export/DL/37562.pdf The data are from the [SOM project][1], and we have used this version: https://doi.org/10.7910/DVN/4FGJTH and the aggregated (contextual) data from https://doi.org/10.7910/DVN/TN3LQF The original SOM data are available at: https://hdl.handle.net/1902.1/17967 The analysis.Rmd file contains the R code for all the models in the article (replication material). For transparency, we have also included some exploratory analyses at the end of the document, including some analyses the reviewers suggests we try. The wp4_party_pos_transposed.csv file contains party positions, as identified by the [SOM project][1]. We have fixed some issues, and left-wing parties are now included in the enhanced SOM data. The ERP-Shares.xlsx spreadsheet makes apparent which parties (and years) we have coded as ERP. [1]: http://som-project.eu