The Nielsen offer aims to recruit users who register to a popular panel that studies the shopping behavior of households and influences the future of consumer goods. Panelists receive a free handheld scanner that they need to use to scan their grocery shopping. For each scan, they receive points that they can redeem for great prizes and vouchers from Nielsen. After registration, respondents are called to confirm the registration and to be given more information, and this is how we measure the quality on this campaign, based on their response on the call.