Such surveys do not result in a random sample because participants are a self-selected group.
But only if it's popular with a self-selected group of internet geeks.
Democracy is normally understood as involving everyone, not just a small self-selected group.
Were the people answering these questions elected to do so by the rest of the protestors or are they a self-selected group?
It is true that Chicago's applicants are a self-selected group with a keen interest in intellectual pursuit.
Only a self-selected group of companies respond to surveys about executive pay packages.
Of course the master's students were a self-selected group, willing to pay almost $40,000 for a degree with no clear career track.
The plan may also be done by a small, self-selected group of residents who ignore input from others in the neighborhood.
They are in essence a self-selected group of untreatable offenders.
Meanwhile, those who bought the policy would be a self-selected group of people likely to have high medical costs.