Local government & planning abstracts

Strand organiser: Greg Ball

Local government and planning: administrative sources - Monday 8 September 4.45pm

Developing a population yield calculator for new residential development
Wil Tonkiss, Ben Corr, Greater London Authority

Accurate estimates of population yield from new housing development are vital for effective service and infrastructure planning. The Greater London Authority Intelligence Unit have recently undertaken a work programme designed to produce a yield calculator which is sensitive both to the type of development proposed and its geographic location. Two concurrent methodologies have been developed; one specifically for child yield (using postcode-level School Census data), the other for total population yield (using 2011 Census data). This presentation outlines the methodologies and provides an overview of the yield calculator as well as practical examples of its application.

Email: william.tonkiss@london.gov.uk

Current and potential uses of Local Authority Council Tax Registers in the Tees Valley
Piers Elias, Tees Valley Unlimited

This presentation examines the current and potential uses of information held on Local Authority Council Tax Registers. ONS used Council Tax registers in their Quality Assurance of the 2011 Census and it provides a comprehensive list of residential addresses along with information on Benefit Claimants, Vacant properties, Second homes and a variety of discount and exemption codes that can help identify certain groups of householder e.g. Single Adults, Students. It will also look at some of the problems of combining Registers from more than one Authority which may be maintained by a different provider (access problems) or with different software (format issues). Tees Valley Unlimited (TVU) stared to collect the data in 2008 to provide background information for Housing Market Renewal and continues to provide annual updates on property bands and Vacancy rates by Local Authority Ward. The new premium payment applied to properties vacant for over two years adds an extra level of detail useful for Housing and Planning Officers. TVU also use the information to inform Local Authority level annual Dwelling and Household Counts and have changed their annual extract date to coincide with Mid Year Estimates. The 2011 Census provided the opportunity to compare results with the data held on the Register at very detailed geographical levels (Output Area) and has helped to identify differences in definition and highlighted how time lags in reporting demolitions or new build can affect results.

Email: piers.elias@teesvalleyunlimited.gov.uk

Using administrative data to estimate the population of Luton and the impact of migration on the area
Eddie Holmes, Luton Borough Council

Luton Borough Council consider that there have been problems with the accuracy of the official population estimates since the 2001 Census and have produced their own population figure since 2006. Further analysis has been carried out to track migration movements using National Insurance registrations from overseas, flag 4 data and the workers registration scheme against the official components of change. School census data has been analysed as an indicator of long term settlement of migrants in the town. This paper presents how local administrative data have been used to quality assure the official population estimates, produce an alternative estimate of the population of Luton and assess the impact of migration on the town.

Email: Edward.holmes@luton.gov.uk

Small Area Population Estimates - Methods, Data Sources and Quality
Fiona Aitchison, Pete Large, Mark Yeomans, Office for National Statistics

The Office for National Statistics (ONS) produces annual mid-year population estimates for a range of small area geographies within England and Wales. The data are important to both central and local government and are used for a range of purposes including the planning and monitoring of services and as denominators in the calculation of a range of rates and indicators. This presentation describes the methods used to produce the estimates for both statistical areas, such as Output Areas and Super Output Areas, and administrative geographies such as wards and parliamentary constituencies. The methods developed in 2013 to revise the time-series of small area mid-year population estimates to be consistent with the results of the 2011 Census will also be discussed. The production of these estimates is dependent on the extensive use of administrative sources, both to measure changes in the general population of an area and to account for static populations such as prisoners and the armed forces. An overview will be given of the different administrative sources used to measure these populations and the various advantages, disadvantages and difficulties associated with using each source. The results of analysis undertaken to assess the accuracy of the small area mid-year population estimates, as measured against the results of the 2011 Census, will also be reported.

Email: fiona.aitchison@ons.gsi.gov.uk

Local government: Policy uses - Tuesday 9 September 9.00am

Understanding current and future patterns of demand for school places: The London Schools Atlas
Ben Corr, Greater London Authority

Planning the provision of sufficient school places for London’s burgeoning school age population has become increasingly challenging in recent years. At the time of the 2011 Census, six of the ten local authorities with the highest proportions of the population aged 0-4 were located in London. As these cohorts make their way to the gates of London’s primary schools, projections show we may need up to 4,000 extra primary classes by the end of the decade. Understanding the spatial distribution of demand, both currently and in the future, will be key to ensuring our delivery models are capable of meeting the statutory obligation upon local authorities to provide a school place for every child. To this end the London Schools Atlas has been developed by the GLA Intelligence Unit to offer an interactive tool for understanding the relationship between where children live and where they go to school. It also allows users to examine how projected changes in the population may impact on demand for places within and across local authority borders in future years. This presentation will cover the steps taken to deliver the Atlas, a demonstration of the insights it can generate and a discussion of our plans for future development.

Email: ben.corr@london.gov.uk

Population data and how it is used to inform policy at the local level: the case of Hampshire
Gemma Quarendon, Jack Cox, Hampshire County Council

We all know how important population data is – both raw counts of the total number of people but also the characteristics of those people, in order to understand what their needs might be now and collectively what they might be in the future. But how does that information get used in practice at the local level? This presentation will look at what population data is produced at Hampshire County Council and how that, as well as other nationally available population data, is then used to help improve the lives of Hampshire residents by informing policy and service planning across a range of service streams. For example, Hampshire County Council produces small area population forecasts of its population annually and those estimates are used extensively to inform a whole raft of policy decisions as well as within service planning including budget planning for future care needs for the elderly; to aid school place planning; and to help feed into a habitat mitigation project for Natural England, to name but a few.

Email: gemma.quarendon@hants.gov.uk

The use of population data in school place planning
Heather Zawada, Hampshire County Council

The Local Authority is under statutory duty to ensure that there are sufficient school places within their area and therefore, forecasting of pupil numbers plays a large role on decision making around building/extending and even moving provision. Predicting school place demand is a complex task. Where children go to school involves a range of different factors such as housing growth, inward and outward migration as well as parental preference. As a result, planning for school places is based on probabilities and not certainties, and whilst pupil forecasts are derived from methodology, they come without a guarantee. Alongside this forecasting, there is also a duty to respond to local need, to raise standards and promote diversity in response to government policy. Internal and external findings on the quality of schools create another angle of investigation as to whether resources are being used effectively. The County Council collects data on the past and present take up of places in all schools in Hampshire that are maintained by the local authority. This information is used together with other sources of station, principally birth and housing data, to predict the future need for school places across the county. This is what is referred to as pupil "Projections" or "Forecasts".

Email: heather.zawada@hants.gov.uk

The importance of small area evidence
Sally Boxall, Basingstoke and Deane Borough Council

Across the public and private sector, decisions are constantly being made on ways to shape our green and pleasant land. Basingstoke and Deane Borough Council makes use of a wide variety of data and research to inform and support local policy and decisions. This talk will focus on specific examples of small area data use to support policy, incorporating the census, MOSAIC and other local and national products. Specific work examples will be confirmed nearer the time, but may well include, supporting the transition to Individual Electoral Registration, new development and regeneration areas, poverty analysis, ward level profiling, boundary issues, and our biennial residents’ satisfaction survey.

Email: sally.kenyon@basingstoke.gov.uk

Understanding the quality of population estimates - Tuesday 9 September 11.00am

Measuring uncertainty in the ONS mid-year estimates: multiple statistical treatments to capture variability around administrative and survey sources
Louisa Blackwell, Cal Ghee, Domenica Rasulo, Demographic Methods Centre, ONS

ONS uses the Cohort Component approach to produce its mid-year population estimates. This involves taking the previous year’s population (the Census is the base), adding births, removing deaths, adjusting for internal and international migration and other minor adjustments. The census, internal and international migration contribute the most to uncertainty. The further we move away from Census, the greater the uncertainty in the estimates becomes. The ONS Demographic Methods Centre has been working with the Southampton Statistical Science Research Institute to create uncertainty measures for the estimates. This involves using the observed data to recreate the mid-year estimates for each of the most influential components many times to generate a range of possible values that could occur. The standard deviation of these distributions then provides a measure of spread for each local authority, for each year. The simulated estimates can then be rolled forward each year. This ensures that the simulated distribution for the composite includes the uncertainty from previous years and new uncertainty for the current year. We also calculate the relative proportions of the combined uncertainty associated with each of the three components. We have updated the modelling for the new 2011 Census estimates and changes in the methods used to create the mid-year estimates. This presentation will demonstrate some of the techniques used in the uncertainty measures. We will present our results in the wider context of the series of quality measures and tools that were released in June 2014 to inform the use of ONS’ mid-year estimates.

Email: louisa.blackwell@ons.gsi.gov.uk

Using administrative data and demographic analysis to quality assure mid-year estimates
Neil Park, Office for National Statistics

Alongside the publication of mid-year population estimates for 2013 ONS published a tool providing access to materials used in their quality assurance. This tool included administrative data on births, child benefit, state school attendance, GP patient registrations and state pensions, by age and sex, used as comparators to the mid-year estimates and demographic analysis of fertility and sex-ratios. While the use of demographic analysis in the QA process of the mid-year estimates is long established the use of administrative comparators in this way is a new development. The use of administrative data brings the QA of the MYEs more in line with the quality assurance processes used for the 2011 Census. This session will cover the design and use of the tool, the merits of using different administrative data sources and the usefulness of demographic analysis, particularly sex-ratios and fertility. High level findings from the quality assurance process will be presented and will focus on the changing relationships between administrative data and mid-year estimates as the estimates are rolled further away from the initial 2011 Census base. The changing distribution of sex-ratios and fertility rates will also be discussed.

Email: neil.park@ons.gov.uk

Visualising the causes of discrepancies in the mid-year estimates
Mark Auckland, Office for National Statistics

The Dynamic Component Risk Tool (DCRT) has been developed to further understanding of the dynamics of the components that drive the mid-year estimates to explain the causes of specific discrepancies in the mid-year estimates. The tool provides a broad overview, aiding understanding and reinforcing the need to consider the impact of each component used to produced the mid-year estimates on the final estimates. It provides a consistent approach to all local authorities by exploring the probable direction and size of discrepancies for each component of the mid-year estimates through a combination of understanding the processes used to derive them and by using administrative comparators where available. For each component (by age/sex) the likely risk of discrepancy is evaluated and assigned to a risk category. By doing this it is possible to identify and display where discrepancies are most likely to have occurred and in what direction they may have pushed the final estimates. This intelligence will be useful when determining the impacts of future methodological improvements on the mid-year estimates as it enables the confounding affects of other components to be understood. The tool is informed by analysis carried out during and after the 2011 Census into the causes of discrepancies between rolled forward and census based estimates. A version of the tool for mid-year estimates rolled forward from the 2011 Census has been produced, this forms part of a suite of quality assurance tools for the mid-year estimates.

Email: mark.auckland@ons.gov.uk

Evaluating plausibility ranges for children
Rebecca Wright, Office for National Statistics

In 2011 ONS produced experimental plausibility ranges based on administrative data for the mid-year population estimates. The publication of estimates based on the 2011 Census allows the validity of the methods underlying these ranges to be evaluated and recommendations about their future development and use to be made. One of the key methods used for evaluating the plausibility ranges involved looking at the number of Census figures that failed to fall within the plausibility ranges. This is a strong indication that the plausibility ranges may not cover the true population in areas where the census failed to validate the ranges. The potential usefulness of the ranges was also assessed, looking at whether the ranges could be providing information about broad trends in the population estimates, as well as whether they provided any intelligence about the quality of the mid-year estimates. In order for plausibility ranges to be a robust indicator of the quality of the mid-year estimates the limitations of the data sources used in the current method will be considered.

Email: rebecca.wright@ons.gsi.gov.uk