Types of errors

• Sampling error

  Error assiciated only with the fact that we work with a sample instead of a whole population
• Non-sampling error

  All other sources of errors, except sampling error
• Sampling frame error

  If some of the population items are not represented within the sampling frame
• Non-response error

  Some sample frame units refuse to participate within sampling process
• Researcher errors

  Errors in the research design (administration, defining the population, whong made questions, etc.)
• Interviewer errors

  Errors due to inappropriate actions of the interviewer
• Respondent errors

  Wrong answers or not answers (willing and unwilling) to questions