City E conducted a public policy poll in which 1,000 people were randomly selected to answer questions  A month later, 1,000 people were again randomly selected to answer the same questions, but in a different order  The results showed that the two samples had different answers to many questions
The second survey changed the first to a real-name survey.
 This proves that the same set of questions, because the order of the questions changes, sometimes results in different answers