Starting in 2003, Planck Working Group 3 (the “CTP”, Cl Temperature and Polarization group) undertook a comparison of mapmaking codes in increasingly realistic situations. The approach to realism proceeded in five steps, named after the locations of working meetings of the group (Cambridge, Helsinki, Paris, Trieste and Randswagen).

Having concluded the mapmaking comparison in 2006, CTP team initiated a systematic comparison of Power Spectrum estimators named after the location of the first meeting for this study: Varenna.

This comparison took further steps of increasing complexity including Likelihoods and Parameter estimation named after the locations of meetings of the group (Pasadena, Rome, London, Cambridge). We expect to finalize this study in this meeting in Porto. This meeting will also initialize the comparison of component separation and Power Spectrum estimators with a view to the ongoing Planck data analysis.