The skin color scale used in the ANES 2012 Time Series Study duplicates the NIS (New Immigrant Survey) scale designed by Douglas S. Massey and Jennifer A. Martin, based on an idea originally developed by Massey, Charles, Lundy, and Fischer (2003) in their work on the National Longitudinal Study of Freshmen.
To rate respondents, interviewers essentially memorize the scale, so that the respondent never sees the chart. Interviewers were rated by data collection managers prior to the field period and were not informed where they themselves were rated on the scale.
Training Instructions for Interviewers
Excerpt from the Interviewer Training Manual:
As you know, human beings display a wide variety of physical attributes. One of these is skin color. Unfortunately it is a reality that some respondents may answer questions differently depending on theirs and your skin tone. They may not be comfortable being honest about their opinions, for example, if they are worried they might offend you. In order to detect such discrimination, it is important that the study include a measure of skin color.
In order to address the potential bias that skin color may introduce, we will ask you to record the skin color of the Respondent using a Scale of Skin Color Darkness. This is an 11-point scale, ranging from zero to 10, with zero representing albinism, or the total absence of color, and 10 representing the darkest possible skin. The eleven shades of skin color are depicted in a chart, with each point represented by a hand, of identical form, but differing in color. You should be careful to assess the Respondent's skin color regardless of his or her race or ethnicity. It is important that you become familiar with the scale so that you do not access it during the interview. Respondents should never see this scale.
You will be asked to record the Respondent's skin tone immediately after you leave the Respondent's home after the Pre-Election Questionnaire. Again, Respondents must never see this scale, so you need to make a mental note of this while you are administering the questionnaire.