Table 2.

Experimental Procedures by Condition

		Condition
Date	Actiona	MTF control	Condition 1: Mail Push	Condition 2: Web Push	Condition 3: Web Push + E-mail
Dec. 13	Selection letter	Cp	Cp	C	C
Dec. 20	Newsletter	Cp	Cp	C	C
Apr. 3	Advance letter	Cp	Cp	Cw	Cw, e-mail
Apr. 10	Questionnaire	P, $	P, $	W, $	W, $, e-mail
Apr. 17	Reminder postcard	Cp	Cp	W	W, e-mail
May 10	Reminder letter	Cp	Cp, Wb	Pc, W	Pc, W, e-mail
May 18	Nonresponse phone call	Cp	Cpw	Cpw	Cpw
Aug. 27	Final mailing	P	Cpw, P, W	Cpw, P, W	Cpw, P, W

Note.— $ = incentive check; C = communication without any mention of questionnaire delivery mode; Cp = communication mentioning the paper questionnaire (not including the actual questionnaire); Cpw = communication mentioning both the paper questionnaire and the web questionnaire; Cw = communication mentioning the web questionnaire instead of the paper questionnaire; E-mail = communication duplicated in an e-mail to those who provided e-mail addresses; P = paper questionnaire; W = web survey log-in information (URL and PIN).

^aAll procedures are communications to the participant based on traditional MTF procedures and are altered minimally in the experimental conditions. All occur via postal mail service except for “e-mail.”

^bThis is the first time Condition 1 respondents are invited to the web questionnaire.

^cThis is the first time Conditions 2 and 3 respondents receive a paper questionnaire.