Reasons for becoming a member of the online panel. Topics: reasons for signing up for an online panel (curiosity, contribution to the improvement of better products and services, financial incentives, novelty, first to know about new products and services, entertainment and fun by answering the panel surveys); number of other online panels enrolled; Materialism (Richins scale after 1987); monetary orientation (money and possession). Demographics: sex; age (in years, in groups, age 31 to 50 years, age group 51 and older); level of education. Also encoded: time to complete the survey (duration in sec); case status (more than 300 seconds active with entry info or previous termination with or without admission information); unknown way of entry into the panel; panel entry through: panel takeover, permission marketing, intercept survey, survey platform, Google AdWords, banner advertisement, referral system); total number of omitted items; straightlining; panel membership tenure in days; number of panel invitations in the last 12 months; number of survey starts in the last 12 months; number of broken-off surveys in the last 12 months; starting rate in the last 12 months; break-off rate in the last 12 months.