Strand 2: Origin - Destination Flow Data Flashcards
What sort of data is Migration and Commuting classed as?
Flow Data/ Interaction Data/ Origin - Destination Statistics
From the Census what sort of data is available for various migration variables?
- Migrant
- Migrant Household
- Wholly Moving Household
What are the 2 types of data available from the 1991 Census about Interaction Data?
- Special Migration Statistics (SMS)
2. Special Workplace Statistics (SWS)
What are the 3 types of data available from the 2001/11 Census about Interaction Data?
- SMS for the UK
- SWS for ENG, WAL, NI
- Special Travel Statistics (STS) for SCOT, includes travel to place of study
What online system do you use to access SWS & SMS from the UK Data Service
WICID - Web-based Interface to the Census Interaction Data (91/01/11) - Also provides re-esimates
SMS is very useful but what problems does it face?
Preserving Confidentiality - ONS are reluctant to provide info and produce data where counts are very small
What was the ONS’ solution to confidentiality issues in 1991?
Suppression
What is Suppression?
The non publication of counts in certain tables
What was wrong with Suppression (1991)?
- Widespread
- Unnecessary
- Prevent Accurate Analysis
Who developed a method to ‘recover’ the suppressed data and have estimated ‘complete’ SMS matrices?
Rees and Duke-Williams (1997)
What is the most detailed and complete source of information on internal migration and immigration in the UK?
CENSUS
What method was used to prevent risk of disclosure in 2001?
Small Cell Adjustment Method (SCAM)
What is the Small Cell Adjustment Method? (SCAM)
- In each table flow counts of 1 and 2 at any one level were adjusted to be 0 or 3
- Meaning at any one level the flows in different tables will not be equal
What does the government use migration data for?
To produce mid-year population projections and estimates
What are other sources of Migration data?
- Labour Force Survey
- International passenger Survey
- National Health Service Central Registers (NHSCR)