Attitudes
Questionnaires are often used to assess attitudes.
Commitment Measures
At the medial level, where we’re concerned with assessing attitude, Agheyisi and Fishman (1970) suggest using commitment measures to do this. Commitment measures are questions designed to evaluate how willing a person is to do something. For example, asking whether the interviewee would let their daughter marry a man from another language group would reveal attitudes towards speakers of that language. They say that these "are more useful than traditional attitude questionnaires for measures which are designed to be validated against overt behaviour, because they directly tap respondents’ behaviour tendency rather than their cognitive or evaluative responses." (p.145)
Bibliography
Agheyisi, Rebecca, and Joshua A. Fishman. “Language Attitude Studies: A brief survey of methodological approaches.” Anthropological Linguistics 12:5, 1970: 137-157.