They're probably using this list https://en.wikipedia.org/wiki/List_of_countries_ranked_by_ethnic_and_cultural_diversity_level https://en.wikipedia.org/wiki/Li

They're probably using this list https://en.wikipedia.org/wiki/List_of_countries_ranked_by_ethnic_and_cultural_diversity_level https://en.wikipedia.org/wiki/List_of_countries_ranked_by_et... And you are probably using this one https://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependent_territories_by_immigrant_population https://en.wikipedia.org/wiki/List_of_sovereign_states_and_d... So it depends what you mean by diversity