BSPS 29 February

Mid-2006 based Subnational Population

Projections – Jonathan Swan SPEaQE

Introduction

• Subnational population projections produced every two years

• Projection by age and sex• Projection for every LA in England• Based on mid-year estimates• Preceded by consultation• Cover 25 years i.e. 2006 based go up to 2031

2006 based Timetable

• February 2008 - Calculation of provisional project’s• 6 March - Start of Consultation• 17 April - End of Consultation• April - Analysis of Consultation Responses

– Reply to responses

• May/June - Final Calculations and QA• June 2008 - (date tba) Main Publication• August 21 - Analysis of Accuracy published• [December 2008 – Earliest date for variants]

Basic Methodology

• Cohort Component Method– Pt+1 = Pt + B – D + M

• Trend Based Projections– Based on Past Trends– Projections not Forecasts– Do not take account of policy considerations

• Top Down– Components Constrained to National Projections– LA as base unit– PCOs by proportional allocation

The Consultation• Part One:• Consultation on Initial Migration Assumptions

– Traditionally done every new base year– Consultation with Local, Health, and Regional

Authorities only– District Level LA lead.

• Part Two– Open to all

• Consultation on Outputs– Internet tables / Tables on Request

• Variants– Demand and Which variants– Methods to be used

Criteria for accepting change during the consultation

• Consultation is focused on the migration assumptions in the first year of projections

• Assumptions are based on recent demographic trends

– Internal Migration based on past 5 years data from patient register

– International Migration based on new MYE methods

• Clear evidence required that the level of migration is incorrect before projections are adjusted

– Major one-off change in employment situation– Areas with high student populations– Consultation paper has more info.

Criteria for accepting change during the consultation (2)

• Dwelling stock plans will not be considered– Unlike GLA, Projections unconstrained by Housing

Capacity– New Housing Estates not directly allowed for

• Inevitable that projections for small areas are prone to greater uncertainty

– Assumptions of fertility and mortality use high quality registration data

– Any RELIABLE migration data will be considered – if it shows a different trend

Syndicate Sessions

• As consultation not out - Change to 3 groups• Modelling Components (Combined group):

– How can we change migration and natural change components to reflect local variation?

– How can this be done systematically?– Can/Should this be related to national variant methods?

• Which Variants Should we do?– Which are the most important scenarios?– What are the driving needs for variants?

• How can we do a housing constrained variant? (new Group)– Which data sources? (Regional plans?)– Using what methodology?– Relationship between housing and population complex.

Rest of day ..

• Syndicate Session will be followed by feedback.

• Then a chance to discuss issues from the day and ask the panel.