Islamisation Index by Comarca in Catalonia

Methodology

The index combines two equally-weighted branches, each on a 0–4 scale. (A) INFRASTRUCTURE: density of Islamic places of worship per 10,000 inhabitants (DGAR, Generalitat): <0.1→0, 0.1–0.5→1, 0.5–1.5→2, 1.5–3→3, >3→4. (B) POPULATION COMPOSITION: the mean of whichever indicators are available — (B1) percentage of residents born in Muslim-majority countries (Idescat register, 2022): <3%→0, 3–8%→1, 8–15%→2, 15–25%→3, >25%→4; and (B2) percentage of residents whose given name belongs to the naming traditions of Morocco and the Maghreb, West Africa, South Asia and the Balkans (Idescat Onomàstica, 2025 census): <1.5%→0, 1.5–2.5%→1, 2.5–3.5%→2, 3.5–4.5%→3, >4.5%→4. B2 measures NAME ORIGIN, not religion: a given name is chosen by parents and reflects a family's cultural tradition, not anyone's belief or practice. It is also a FLOOR, because Idescat suppresses any figure below 4 for statistical confidentiality and names shared with European traditions (Sara, Adam, Omar, Nadia…) are deliberately excluded. In 18 comarques the suppression is too heavy for the figure to be reliable and it is omitted; there, composition rests on B1 alone. If only one branch has data, that branch alone is used. The thresholds above are band boundaries, but the score is CONTINUOUS: a value falling between two thresholds takes its proportional position within that band, so two comarques inside the same band are not tied. The top band, being open-ended, saturates at 4. The map uses a neutral five-band single-hue scale (light = lowest index, dark = highest), with no good/bad connotation.