The different stages of the survey ensure that the process meets the requirements for statistical production:            
- stratified sample selection 
- reminders and checks of data being collected 
- clearance 
- adjustment for total non-response 
- shimming 
- adjustment for partial non-response 
- winsorisation (control of the influence of atypical units)
- the questionnaire was tested (in the 4th quarter 2012) as part of the survey's appearance before the label committee in early 2013.