methods of collecting data
census: held every 10 years, Britain uses the de facto method, which records where people live on the day of census, legally required, finds social, economic and cultural background, for the gov. to know how to spend money, plan for future
civil registration: records can be kept of vital events (marriage, birth, death), without these it's impossible to get passports, reliable
Scottish Household Survey: continuous, voluntary, interviewer-administrated, sample of population - 10,000 /yr
border control: information gathered on people entering and leaving the UK