Incorporating recent trends in household formation into household projections for Scotland Esther Roughsedge Household Estimates and Projections Branch National Records of Scotland (NRS) November 2014

Outline Introduction to household projections for Scotland. Long-term trends in household formation. Recent trends. Changes to the projections methodology for the 2012-base household projections. Results Other relevant trends

What are household projections? Produced every two years – most recent set 2012-based. Projections of the number of households 25 years into the future, by: –Council area –Age of head of household –Household type Projections are based on past trends. They are not forecasts – we don’t attempt to account for future economic or social changes. Used for informing planning decisions Lots of overlaps in the trends and methods used in different parts of the UK.

Trends in household formation

Household numbers rising faster than population …

…more people living alone and in smaller households…

…but annual household growth has levelled off recently…

…and the fall in average household size has levelled off

What impact have these trends had on the household projections?

Households by type 1991, 2001 & 2011…

…including the 2011 Census data

So in the 2010-based projections we: –Over-projected the increase in smaller household types –Over-projected the reduction in larger household types. –Over-projected the total increase in household numbers. The trends in household formation were based on the 1991 and 2001 Censuses only. We produced a number of variants, including an ‘alternative headship’ variant projection, which was more accurate.

For the 2012-based projections data from the 2011 Census was available. So we reviewed our method to decide how best to include this data (and possibly other sources)

How are the household projections produced?

Household projections method Take NRS population projections; Subtract population living in communal establishments, e.g. student halls, barracks, care home); Project forward information on household type (‘headship rates’), e.g. single adult, two adults plus children –Used to use two censuses (1991 and 2001). Used a modified 2-point exponential function. –Now we have the 2011 Census available as well.

Old method - trends based on 1991 and 2001 Censuses

2011 Census data – change in trends

Project forward newer trends only?

Project longer term trend only?

Incorporate both recent and longer term trends - weighted using survey data

New method of projecting household type To make use of three censuses, two sets of projected headship rates were produced using the modified two-point exponential model. i.Using 1991 and 2001 Censuses ii.Using 2001 and 2011 Censuses They were combined into a single set of headship rates, using survey data from the Scottish Household Survey. Weights chosen to minimise the difference between the survey data and the household projection. For 2012 the weights were 0.75 towards and 0.25 towards Allows up-to-date household type data to be included into the projections. –Increasingly important as we move further away from the last census.

Calculate the household projection Number of heads of household = Private household population * Headship rate This is done for each area, age group and household type for each year Number of heads of household => number of households We make some adjustments to ensure consistency with population projections and household estimates, which are based on Council Tax data. Unchanged since previous projections.

Household projections results

Average household size is falling…

The population is ageing…

And older people are most likely to live alone

How have the trends changed since the previous projections?

The new set of projections are lower than the previous set 2010-based household projections (previous projections): +23% over next 25 years 531,000 new households (21,200/year) 2012-based household projections (new projections): +17% over next 25 years 396,000 new households (15,800/year)

Comparison with 2010-based projections

Increase in young males living alone is smaller than previously projected, also applies to young females

Reduction in 3+ adult households headed by 45-64yr olds is lower than projected previously.

Other relevant trends

Young adults Source: Census

Young adults More young adults are living with parents, and fewer are living as a couple Source: Census

Tenure by age, 2001 & 2011 Source: Census

Tenure by age, 2001 & 2011 Source: Census

Tenure by age, 2001 & 2011 Source: Census

Trends in house-building Source: Scottish Government Housing Statistics for Scotland 2014

Summary - Method Over the past decade the growth in household numbers has slowed. Our previous projections didn’t fully capture this trend as they used only 1991 and 2001 Censuses based projections use 1991, 2001 and 2011 Censuses and survey data for weighting – they include recent and longer-term trends.

Summary - Results Household numbers are still increasing, but by less than in previous projections. Biggest changes are among young adults: –Fewer living alone or in couples. –More living with parents. –More renting.

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