Data convincingly show that the 2010 national exit poll severely misestimated the Latino vote. Whereas the Latino Decisions poll estimates differ significantly from the network exit polls and this raises the question of whether there is a systematic flaw.
Examination of interviews, statistical properties of the resulting samples, uneven distribution of minority populations, and the low incidence of bilingual interviewing all suggest that the typical exit poll estimates reported in the National Exit Pool surveys, systematically underestimate Latino and African-American Democratic vote share by over-representing higher income, higher education, and more socially integrated minority voters than their share of the electorate warrants.
Very few in the media have expertise in polling Latinos and analyzing Latino vote data, and as a result are not in a position to assess on election night the veracity of the Latino results. Assimilated, middle-class, and English dominant respondents are over-represented while poorer, socially segregated, and Spanish dominant respondents are underrepresented. The result, inevitably, is a conservative or pro-GOP bias.
Another reason for the erroneous exit poll figures is that Spanish language interviewing is available only on a limited basis.