OPINION POLLS

• Personal interviews e.g. aggregation of opinion of sales representatives to obtain sales forecast of a region
  - Knowledge base (experience) Subjective bias
  
  
• Questionnaire method
  - questionnaire design
  - choice of respondents
  - obtaining responses
  - analysis and presentation of results (forecasting)
  
  
• Telephonic conversation
  - Fast
  
  
• DELPHI