The Wave 2 experiment compared a formal letter on printed stationery with a greeting card type format. The messages in cards and letters were equal in length, text, incentives, and information related to legitimacy of the study and privacy concerns. Thus, differences were only in appearance and format. The envelopes for both cards and letters were personally addressed. The letter was also personally addressed internally. The experimental treatments were as follows:
1 Aformal letter on printed letterhead stationery with the survey logo
2 A card in a greeting card format
Within PSUs, households were randomly allocated to one of two treatment groups and all eligible respondents in the household were treated the same. The controlling variable is b_ff_advance on the record b_hhsamp_ip.
