Beginning in 1996, the American Community Survey question was worded "Is this person Spanish/Hispanic/Latino?" In 2008, the question wording changed to "Is this person of Hispanic, Latino, or Spanish origin?" From 1999 to 2007, the Hispanic origin question provided an instruction, "Mark (X) the "
No" box if
not Spanish/Hispanic/Latino." The 2008 question, as well as the 1996 to 1998 questions, did not have this instruction. In addition, in 2008, the "Yes, another Hispanic, Latino, or Spanish" category provided examples of other Hispanic origin groups (such as "Argentinean," "Dominican," "Salvadoran"). Results from the 2003 National Census Test showed that adding the term "origin" to the Hispanic origin question and adding examples to the "Other Hispanic" category reduced reporting of generic responses such as Hispanic, Latino, and Spanish thus improving the reporting of detailed Hispanic origins. The percentage identifying as Hispanic was not affected, see "2003 National Census Test"
http://www.census.gov/srd/papers/pdf/rsm2007-34.pdf