​​From millionaires to Muslims, small subgroups of the population seem much larger to many Americans

 Americans tend to vastly overestimate the size of minority groups. This holds for sexual minorities, including the proportion of 

• gays and lesbians (estimate: 30%, true: 3%), 
• bisexuals (estimate: 29%, true: 4%), and 
• people who are transgender (estimate: 21%, true: 0.6%). 

It also applies to religious minorities, such as 

• Muslim Americans (estimate: 27%, true: 1%) and 
• Jewish Americans (estimate: 30%, true: 2%). 

And we find the same sorts of overestimates for racial and ethnic minorities, such as 

• Native Americans (estimate: 27%, true: 1%), 
• Asian Americans (estimate: 29%, true: 6%), and 
• Black Americans (estimate: 41%, true: 12%).

A parallel pattern emerges when we look at estimates of majority groups: People tend to underestimate rather than overestimate their size relative to their actual share of the adult population. For instance, we find that people underestimate the proportion of American adults who are 

• Christian (estimate: 58%, true: 70%) and the 
• the proportion who have at least a high school degree (estimate: 65%, true: 89%). 

The most accurate estimates involved groups whose real proportion fell right around 50%, including the percentage of 

• American adults who are married (estimate: 55%, true: 51%) and 
• have at least one child (estimate: 58%, true: 57%).

Misperceptions of the size of minority groups have been identified in prior surveys, which observers have often attributed to social causes: fear of out-groups, lack of personal exposure, or portrayals in the media. Yet consistent with prior research, we find that the tendency to misestimate the size of demographic groups is actually one instance of a broader tendency to overestimate small proportions and underestimate large ones, regardless of the topic. 

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