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.