This experiment compared different methods of sending out the unconditional incentives that are sent to respondents with the prenotification letter. Using e-vouchers gives participants a greater choice in the type of incentive they receive. Rather than being restricted to physical Love2Shop gift-cards which must be used in physical stores, PERKs would let participants choose vouchers that can be used online or a donation to charity, alongside the Love2Shop gift-card.
Adult sample members eligible for unconditional incentive were randomly allocated to two groups. One received the Love2Shop gift-card as standard. The second group was invited to go online and claim their unconditional PERKs voucher. This experiment affected the participant advance materials. There were also some ‘motivational’ messages added to the letter experimentally: (i) no additional message, (ii) e-incentives are more eco-friendly, (iii) e-incentives are easier to use, and (iv) both messages. Households were allocated to treatment groups in equal proportions. The allocation variables are in file p_hhsamp_ip:
ff_perksw16 (1/2 each, allocation stratified by sampleorig ff_gridmodew16 ff_incentw16 n_gor_dv)
1 = Receive incentive as usual
2 = Online option
ff_perksmsgw16 (1/4 each, allocation stratified by sampleorig ff_gridmodew16 ff_incentw16 n_gor_dv)
1 = No message
2 = Eco-friendly
3 = Easier
4 = Both
