To avoid fraud and reduce the likelihood of participants
completing the study multiple times, verification
procedures were enacted: participants’ Internet protocol
(IP) addresses were checked to verify U.S. location; participants’
names, e-mail addresses, mailing addresses, and
IP addresses were checked for duplication; and public
Facebook information was reviewed. To receive compensation,
participants provided their name and mailing
address for electronic gift cards and were informed that
due to credit card fraud detection policies the card would
be unusable unless the shipping address used for purchases
matched the address they provided. Any suspicious
cases were sent an e-mail requesting they provide further
information to verify their identity and=or eligibility.