new scheme hopes set up by biostatisticians from the university of michigan and is available over 18s in the us .
it was set up by biostatisticians from the university of michigan and although the app is hosted by facebook , the site is not affiliated with the scheme in any other way that the app is available for free from facebook 's store but only currently open to people aged over 18 with a valid mailing address in the us .
once a user has read and accepted the terms and conditions they are presented with health surveys they can complete each day .