POPGROUP Derived Forecasts Module: Integrated Demographic Model

1. The Derived Forecasts module of the POPGROUP softwareLudi Simpson, University of ManchesterBSPS day meeting on household projection models, 16th July 2012, LSE

2. UK industry standard for sub-national areas • An integrated demographic model for planning and research • population, households, labour force, disability, … • local and central government information • small area and District, • District, County/Region/National • a demographic framework, data to fill it, and an analysis tool • historical series and new census data • estimates and forecasts • official projections and user’s own scenarios • Excel platform

3. POPGROUP users 2012 • 90+ organisations • Mainly UK public sector • Welsh Assembly for LA projections • Scottish User Group supported by NRS • Educational license: free for teaching • Commercial sector use growing: the industry standard for UK local planning Local authorities

4. Popgroup management • Developed collaboratively • Origins: 6 local authorities co-funded in 1999 • Ownership: Local Government Association since 2009 • £1500 POPGROUP, £1500 Derived Forecasts, one-off price • Data Modules £450 a year, replicate official projections • Programming and technical support • popgroup@edgeanalytics.co.uk • Ludi Simpson technical specification / support • Steering Committee – users, and Wales/Scotland reps, • Andrew Rudd arudd@worcestershire.gov.uk • Independent user group • Charlotte Devereux cdevereux@herefordshire.gov.uk • Web site and email discussion list, http://www.ccsr.ac.uk/popgroup/ • Training – online, 2-day annual course, manuals

5. POPGROUP & policy scenarios - Not in households x Headship rates Population Households x Activity rates Revised migration Compare with housing supply Sharing, Vacancy rates, Second homes, Housing land Labour force Compare with jobs supply Unemployment, Commuting, Jobs creation

6. Presentation Demographic framework • POPGROUP population forecasts framework • Derived Forecasts framework • UK household projections frameworks • Demonstration of Derived Forecasts model setup Data and analysis • Demonstration of a household projections Data Module • Demonstration of reports from a household projection • Demonstration of a housing-led population forecast

7. POPGROUP population forecasts framework • Standard cohort component methodology • Single year of age, to 90+ • Gross migration with two external areas • Schedules of births, deaths, migration may change over time • Special populations can be separate, eg Armed Forces • Projection of multiple ‘Groups’, named by user • Districts in a Region, national areas, small areas within a district, ethnic groups within a district • Accepts counts and rates, estimating the missing items • Counts take precedence: initial rates are re-estimated: • Time series of past data and forecasts • ‘Forecasts’ with past population provide estimated rates and migration flows

8. Derived Forecasts framework Households = Population (adjusted to deduct those not in households) * age-sex-specific headship rate (for each household type) In defence of the ‘headship rates’ approach • Household types can include size of household (Scotland, Wales) • ‘Head’ can be a reference person, independent of changing cultural norms (England, Wales, Scotland) • The same approach can use ‘membership rates’ in which non-heads are included in the output (Wales) • The number of households is derived by dividing by the number of people in a household type by its household size

9. Derived Forecasts framework

10. Population Forecast Population Forecast Derived Category Rates Population forecast by age and sex by age and sex By age and sex (e.g. headship rates, disability rates) Derived Category Forecast Forecast for Derived Categories (e.g. Households, disability) Derived Forecasts framework D =Derived Category Forecast P =Population ‘at risk’ Forecast R =Derived Category Rates D a,s,u,y,d,g = P a,s,u,y,g * R a,s,u,y,d,g / 100 a = age-group s = sex u = Sub-population y = year d = derived category g = group (usually an area, but can be an ethnic group or social group)

11. Derived Forecasts – Model Setup

17. Using DF within POPGROUP cons.xls DFSupply.xls

18. The impact on population of a housing plan

19. PopGroup All Category: Total 480,000 460,000 440,000 420,000 Proj_ID 400,000 Migration-led Migration-led revised Natural Change 380,000 SNPP 2008 360,000 340,000 320,000 300,000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 Year DF - comparison of scenarios DFCompare.xls Example: Leeds Household impact of alternative population forecasts Households

20. Peter Boden pete@edgeanalytics.co.uk Richard Culf richard@edgeanalytics.co.uk

21. Observations • POPGROUP • aims to satisfy local planning needs • replicates official ‘trend’ projections • is not restricted to any time or place • does not (yet) support projection of rates from a past time series • Relies on work external to model • encourages users’ own policy-led scenarios and alternative demographic assumptions