I want to make a marketing experiment (sending an e-mail) with fractional factorial design. I will send this e-mail to a mailing list consist of 660 members. I have 6 factors and use the 1/2 fraction. I plan to use response variable open rate (ratio between email open/sent) and CTR (ratio between click/open). But I have individual covariate data which is categorized in three categories (for example: director, manager, staff). If i use the response variable the data should be aggregate, and i should divide 660/32 = 20 recipient per e-mail. But how can I overcome with the covariate? Should I divide the covariate evenly to the groups? Or should I just use individual level data and change my response variable to click (click or no) and open (open or no). I am very confused about this.
Thank you!
Thank you!