Many US citizens have little understanding of statistics creating distrust. Govt has been caught using poor methods and govt individuals have been caught fudging - justifying distrust. Some Citizens are tired of the incessant surveying and may no longer provide data: I'm in this category.  With the rapid loss of privacy in this country I suspect fewer people cooperate - the Gov really cannot guarantee privacy. The extreme politics, and privacy breaches, esp around stuff like guns or drugs -its almost stupid for the Govt to  try to make estimates - I bet MANY gun users refuse to provide ANY info to ANY survey.  Recent example of poor practice by Govt: in AK bush. The Census Bureau is trying to survey me about my community. They mailed letters to MY STREET ADDRESS!!!!!!!! My community finally does have street addresses (ca. 1995)  MOST of the Bush don't have home mail delivery - duhhhh! I contacted Sen Sullivan's office - this could really distort data on  bush AK and affect Fed programs