Household Analysis Review Group 12 April 2011 Incorporating Survey Data in Household Projections NRS: Household Estimates and Projections
Background Household Projections are calculated using � Most recent population projections � With updated CE data � The most recent household estimates but � Estimates for the number of households of each type are projected forward from the 1991 and 2001 Censuses
2008-based Household Projections 2008 Household Types 1 adult, 1 child 1 adult, 2+ children 2 adults 3 person households 795,890 3+ adults 2 person households All 694,570 Households 2+ adults, 2,331,250 1+ children 1 adult male 840,790 1 person households 1 adult female
Projected numbers of household types, Scotland 1,000,000 2008 +23% 2033 800,000 +44% +56% 600,000 -27% 400,000 -27% +56% 200,000 +33% 0 1 adult male 1 adult female 2 adults 1 adult, 1 child 1 adult, 2+ 2+ adult, 1+ 3+ adults, no children children children
Survey Data The Scottish Household Survey (SHS) � Covers approximately 15,000 households per year Labour Force (LFS) and Annual Population Surveys (APS) � LF survey covered approximately 8,000 households � In 2003 the LFS was boosted to 23,000 households and is now renamed the APS
Comparing Survey proportions and projected Census proportions SCOTLAND - 2+ adults, 1+ children 26% LFS 24% 22% APS Census points SHS 20% adj SHS Projections 18% Projections adj SHS LFS APS 16% Census SHS 14% 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Comparing Survey proportions and projected Census proportions SCOTLAND - 1 adult: female 22% Census points Projections 20% adj SHS SHS APS LFS 18% Projections adj SHS LFS APS Census SHS 16% 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Combining Survey and Projected data � SHS data was used as it can be calibrated to 2001 proportions � To reflect uncertainty over accuracy of survey data a maximum weight of 50% was decided on, linked to the time since the last census. � To overcome some of the variability in the survey data a 3 year smoothed average was used.
Projected proportions adjusted using 3 year smoothed SHS data SCOTLAND - 1 adult: female - 3 year smoothed SHS data 22% 3 year smoothed adj SHS adj projections 02-04 adj projections 04-06 21% adj projections 06-08 Projections 20% 19% Smoothed average for Adjusted projection 2006, 2007, 2008 18% 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Diagram of Processing Project Calculate private headship rates population from CE from 1991 and data and the Carry out 2001 census population projection minimum adult and minimum child adjustments Calculate household projection Sum Authorities to get Scotland figures Adjust SHS Constrain to Constrain to Control LA household GROS Scottish SHS figures to proportions to 2001 household type household Scottish Totals Census proportions estimates proportions Reformat and output results
Comparing Scotland Results 2008 2033 Household size Household type unadjusted shs adjusted unadjusted shs adjusted One person 1 adult male 370,160 367,720 578,060 573,760 households 1 adult female 470,630 465,020 675,940 667,510 Two person 2 adults 701,910 701,310 865,670 865,300 households 1 adult, 1 child 93,980 92,860 146,410 144,360 3+ person 1 adult, 2+ children 68,900 66,350 91,450 87,880 households 2+ adult 1+ children 433,420 437,980 314,970 318,060 3+ person all adult 192,250 200,010 140,000 145,530 All households 2,331,250 2,331,250 2,812,500 2,802,400
Scotland, Household types, percentage difference from unadjusted projections to SHS adjusted projections 5% 2008 4% 2033 3% Percentage Difference 2% 1% 0% -1% -2% -3% -4% -5% 1 adult male 1 adult 2 adults 1 adult, 1 1 adult, 2+ 2+ adult, 1+ 3+ adults, no female child children children children Household type
Percentage Difference -0.6% -0.5% -0.4% -0.3% -0.2% -0.1% 0.0% adjusted projections in 2033 difference from unadjusted projections to SHS Local Authority, Household types, percentage Aberdeen City Aberdeenshire Angus Argyll & Bute Clackmannanshire Dumfries & Galloway Dundee City East Ayrshire East Dunbartonshire East Lothian East Renfrewshire Edinburgh, City of Eilean Siar Falkirk Fife Glasgow City Highland Inverclyde Midlothian Moray North Ayrshire North Lanarkshire Orkney Islands Perth & Kinross Renfrewshire Scottish Borders Shetland Islands South Ayrshire South Lanarkshire Stirling West Dunbartonshire West Lothian
HARG members are asked to comment on the analysis presented here and consider whether it is be appropriate to make adjustments to future household projections using survey data.
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