Amercians tend to vastly overestimate the small population sizes

A very good article with very good information.  From ​​From millionaires to Muslims, small subgroups of the population seem much larger to many Americans by Taylor Orth.  

When it comes to estimating the size of demographic groups, Americans rarely get it right. In two recent YouGov polls, we asked respondents to guess the percentage (ranging from 0% to 100%) of American adults who are members of 43 different groups, including racial and religious groups, as well as other less frequently studied groups, such as pet owners and those who are left-handed. 

When people’s average perceptions of group sizes are compared to actual population estimates, an intriguing pattern emerges: Amercians 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%).

Click to enlarge.

There are only five topics where Americans are within three or four points of estimating the correct answer.  

How many households with a household income over $100,000 (Actual 34%, Estimate 38%);

  

Are Republicans (Actual 47%, Estimate 50%); 

Are married (Actual 34%, Estimate 38%); 

Have at least one child (Actual 34%, Estimate 38%); 

Voted in the 2020 election (Actual 34%, Estimate 38%); 

Importantly:

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. 

If exaggerated perceptions of minority groups’ share of the American population are due to fear, we would expect estimates of those groups’ share that are made by the groups’ members to be more accurate than those made by others. We tested this theory on minority groups that were represented by at least 100 respondents within our sample and found that they were no better (and often worse) than non-group members at guessing the relative size of the minority group they belong to. 

Black Americans estimate that, on average, Black people make up 52% of the U.S. adult population; non-Black Americans estimate the proportion is roughly 39%, closer to the real figure of 12%. First-generation immigrants we surveyed estimate that first-generation immigrants account for 40% of U.S. adults, while non-immigrants guess it is around 31%, closer to the actual figure of 14%.

Although there is some question-by-question variability, the results from our survey show that inaccurate perceptions of group size are not limited to the types of socially charged group divisions typically explored in similar studies: race, religion, sexuality, education, and income. Americans are equally likely to misestimate the size of less widely discussed groups, such as adults who are left-handed. While respondents estimated that 34% of U.S. adults are left-handed, the real estimate lies closer to 10-12%. Similar misperceptions are found regarding the proportion of American adults who own a pet, have read a book in the past year, or reside in various cities or states. This suggests that errors in judgment are not due to the specific context surrounding a certain group.

These sorts of systemic estimating errors perhaps sheds some light on various ideological obsessions.  For example, the whole BLM issue a couple of years ago seems, to an empirical rationalist with a good handle on actual reality, to be much ado about nothing.  Studies indicate that police shootings occur in proportion to group propensities to commit crime and African-Americans are only 13% of the population anyway.  In other words, no real effect size to the issue and only relevant to a small percentage of the population.  

However, if one were an average citizen, the issue might seem much more compelling if one believed that 41% of the population were black and even more compelling if one were black and believed that 52% of the population were black.  Even if there was only a small effect size, if it affected half the population, it might command attention.