Lucky: | You wrote to my question about anonymous questionnarires: | | > Correlation is easy; assign people consecutive numbers or | >somesuch. If both participants are anonymous, no problem. Could you | >bring by the questionnaire by hand, in exchange for cash? | | No, they are too far away. | | >If not, how | >about a money order and a PO box? | | They would still need my name. I think its Duncan who's been talking about secured credit cards. As long as the intent is not to defraud, you can call yourself whatever you want and its legal. So create a temporary psuedonym. | > The audit part of this is the tough part. Would the HHS care | >to agree to a broadcast means of verification? Would participants 44, | >71 and 94 please come into the re-testing center to verify their | >participation? There could be a zero knowledge proof of some type to | >demonstrate that you are really patient 94. | | Can someone suggest a way to accomplish all this? With tools that exist no less. Each participant gets a penet account, and agrees to maintain it for (some time period). Part of their payment is withheld as assurance that the account will be maintained. Each participant chooses a passphrase, and feeds that to S/key, providing the 100th md4 hash of their secret passphrase. They enclose this number in their encrypted response form. They also enclose their participant ID #, and an address. When HHS asks for verification that the participants were real, they select a random set of penet IDs, and mails each of them, asking that they show up, bringing a lawyer to protect them from HHS intimidation and the 99th md4 hash of their secret passphrase. They have thus demonstrated who they are, and can answer questions as they feel relate to them not being in colusion with the researchers. I think that deciding whether or not this is useful would require reading the regulations imposed on the researchers by the agency administering the grant. Adam