ESD mats generally have two wire connections, one from the mat to earth ground such as the screw that holds a wall outlet plate, and the other is a conductive wrist strap that grounds you to the matt/ to the wall plate. If you put a matt down on the ground/carpet that is grounded (to the wall plate) and you are wearing shoes that are not conductive - its not going to work. Either you are barefoot, or your shoes have to be conductive to provide a ground path for you. You could instead use a touch pad such as the following -
Amazon.com: Anti-Static Touch Pad Touch Pad & Grounding Cord: Home & Kitchen.
FWIW, I use an ESD pad for my table platter mat - but its not for grounding me (but if I touch my metal platter it will ground me), and if you are interested the details are here with discussion and links for reports/test on record static http://www.vpiforum.com/viewtopic.php?f=7&t=17186#p65882
FWIW, I use an ESD pad for my table platter mat - but its not for grounding me (but if I touch my metal platter it will ground me), and if you are interested the details are here with discussion and links for reports/test on record static http://www.vpiforum.com/viewtopic.php?f=7&t=17186#p65882