Preventing bots

How can I prevent fraud/bots filling in my survey?

We have several methods we use internally and hope to publish them for general use at a later date.

For now look for

  • repeated IPs
  • speeders
  • patterned responses
  • incident rates getting better over time
  • nonsense text in open text fields
  • known distributions not matching data e.g. 50% gender splits

These evaluations can be performed post collection and respondents removed from the dataset.

To prevent users from reentering the survey, a cookie script can be implemented

Dear Nayara, how is the cookie script implemented? Please elaborate.