Population and Household Forecasts Emerging Approach Edge Analytics Ltd Leeds Innovations Centre 103, Clarendon Rd Leeds LS2 9DF Tel: 0113384 6087 contact@edgeanalytics.co.uk February 2012
Table of Contents 1 Introduction... 3 1.1 Background... 3 1.2 Requirements... 3 1.3 POPGROUP... 3 1.4 Document structure... 4 2 Summary of results... 5 2.1 What has been provided?... 5 2.2 POPGROUP scenario summaries... 5 2.3 Household scenario summaries... 15 2.4 Labour force scenario summaries... 19 3 Appendix: Data Inputs and assumptions... 23 3.1 Population... 23 3.2 Births and fertility... 23 3.3 Deaths and mortality... 24 3.4 Migration... 25 3.5 Households... 25 3.6 Dwellings... 26 3.7 Labour Force... 29 4 Appendix: Methodology summary... 30 The authors of this report do not accept liability for any costs or consequential loss involved following the use of the work referred to here, which are entirely the responsibility of the users of the work. Edge Analytics Ltd 2
1 Introduction 1.1 Background Since 2006/7 and the onset of the economic recession, new dwelling completions have fallen considerably. Housing development plans are now outdated given the prevailing economic conditions and the judgement from the new Government that previous Regional Spatial Strategy (RSS) dwelling targets are largely redundant. North Northamptonshire Joint Planning Unit (NNJPU), with responsibility for Corby, East Northamptonshire, Kettering and Wellingborough is seeking a revised evidence base on which to develop a new land strategy based on an achievable house-building trajectory. 1.2 Requirements This report presents an update to projections analysis produced for NNJPU earlier in 2011. NNJPU wishes to produce population, household and labour-force projections for a combination of district and sub-district areas as follows: 1. Corby 2. Four Towns (East Northamptonshire) 3. Rural North, Oundle and Thrapston (East Northamptonshire) 4. Kettering (Kettering Borough) 5. Rothwell and Desborough (Kettering Borough) 6. Wellingborough For the development of its new housing strategy, NNJPU is seeking to evaluate the following growth scenarios: 1. Trend-based (migration-led) scenario 2. Natural change (zero migration) scenario 3. Dwelling-led scenario For each scenario, the population, household and labour force implications of the growth trajectory is required. 1.3 POPGROUP Scenarios have been run using the POPGROUP suite of software. POPGROUP is a family of demographic models developed to forecast population, households and the labour force for areas and social groups. POPGROUP incorporates a cohort component methodology for its population projection model, a headship rate model for its household projection model and an economic activity rate model for its labour-force projection model. The household and labour force projections have been delivered using the Derived Forecast model, a new module in the POPGROUP suite. POPGROUP is used by over 100 local and regional organisations in the UK and has been subject to extensive enhancement and development over the last ten years. It uses MS Excel workbooks to manage its data inputs and outputs and provides great flexibility to enable users to experiment and analyse alternative forecasts. Edge Analytics Ltd 3
1.4 Document structure The main body of this Report provides a summary of the output produced from each of the scenarios. The Appendix provides further guidance on the data, methodology and assumptions used in the development of the alternative forecasts. Edge Analytics Ltd 4
2 Summary of results 2.1 What has been provided? This project has delivered population, household and labour force forecasts for the combination of districts and sub-districts that constitute North Northamptonshire: Corby, Four Towns, Rural North, Oundle and Thrapston, Kettering, Rothwell and Desborough, Wellingborough A number of alternative POPGROUP scenarios have been defined as follows: Scenarios 1 scenario_ scenario which uses recent evidence to derive assumptions about future fertility, mortality and migration. Future migration assumptions are based on the latest five years of historical evidence 2004/5 2008/9. 2 scenario_ - scenario using revised population constraints to derive assumptions about future fertility, mortality and migration. These revised population constraints are based on alternative estimates of immigration for 2001-2009, for each area. Future migration assumptions are based on the latest five years of historical evidence 2004/5 2008/9. 3 scenario_ Natural Change Natural Change forecast which is constrained by zero net international and internal migration each year with a 2009 base therefore meaning that births and deaths are the only components of change. 4 scenario_emerging Approach (A) Dwelling-led forecast with supply constraints from 2010/11 to 2030/31 based upon Emerging Approach dwelling numbers. 5 scenario_emerging Approach_B Dwelling-led forecast with supply constraints from 2010/11 to 2030/31 based upon Emerging Approach dwelling numbers with an additional modification to the Wellingborough trajectory. 2.2 POPGROUP scenario summaries This section provides an illustration of the population forecasts produced from each of the defined scenarios; for North Northamptonshire in total and then each of its small areas. In each case, a chart illustration is accompanied by its corresponding table of data. The dwelling-led scenarios are evaluated against three additional scenarios: migration-led, natural change and a migration-led. The dwelling-led scenarios are policy- Edge Analytics Ltd 5
constrained scenarios and evaluate the population impact of a defined trajectory of dwelling development in each geographical area. The migration-led scenario is based on an extrapolation of demographic trends that have been evident in each geographical area over the last five years for which historical data is available (2005-2009). It differs from the ONS official sub-national projection, which has a 2008-base and uses historical evidence from 2004-2008 as the basis for the calibration of future trends in migration. To calibrate future assumptions, the migration-led scenario uses official statistics on historical population, births, deaths, internal and international migration (for Corby and Wellingborough districts). For the sub-district areas, migration estimates are derived as a residual after taking account of births and deaths in each mid-year estimate. The migration-led scenario is the closest approximation to the ONS SNPP for North Northamptonshire, although there is a 2% difference in the forecast population total in 2031, approximately 370k from the SNPP, 363k from the migration-led scenario. These differences will be primarily due to the different assumptions and impact of migration over the projection period. Using the migration-led assumptions, an alternative natural change scenario is evaluated. This sets the net impact of migration to zero in each year of the projection year. Population growth is driven solely by natural change (births less deaths) with no internal or international migration impact applicable. An alternative perspective on recent population change and therefore future growth, has been evaluated using what has been called a migration-led scenario. Since 2004, there has been much debate regarding the robustness of the official estimates of international migration, which have had a substantial impact upon population growth since the last Census. A number of local authorities in England have consistently challenged the validity of their mid-year estimates, typically arguing that they are too low based upon other, local statistical evidence. Research at the University Leeds has examined the impact of official international migration estimation methods upon mid-year estimates and has identified inconsistencies in the way these estimates have been derived. These inconsistencies have led to both under and over estimation of international migration in local areas and thus under and overestimation of mid-year populations. A copy of this research output can be found at the following link: http://arxiv.org/ftp/arxiv/papers/0903/0903.0507.pdf Using a combination of administrative data sources (GP registrations, National Insurance number (NINO) registrations and foreign student statistics) in conjunction with ONS official statistics on international migration, a model has been built which derives an alternative estimate of immigration. This estimate is scaled more closely to the local evidence from these administrative sources, removing the substantial sampling error issues which are evident in the ONS estimates. Using this model, an evaluation of the robustness of the immigration estimates for the North Northamptonshire study area has been undertaken. This analysis has revealed a likely undercount in the immigration estimates for the area, particularly in Corby. A revised set of mid-year population estimates have been generated for each geographical area, based Edge Analytics Ltd 6
upon a re-calculated estimate of the impact of immigration since 2004. In Corby, for example, the latest mid-year population estimate (2009) has been re-scaled from 55.2k to 58.1k, an additional 2,900 (+5.3%). These new historical population estimates have then been used to derive an alternative set of migration-led assumptions (changing the historical impact of migration, changes the assumptions applied in the population forecasts). These results are presented in the migration-led scenario outputs. Edge Analytics Ltd 7
North Northamptonshire Population Forecasts North Northamptonshire - Population growth - Natural Change Emerging Approach A Emerging Approach B 2001 285,093 285,093 285,093 285,093 285,093 2002 287,477 288,040 287,477 287,477 287,477 2003 290,397 291,187 290,397 290,397 290,397 2004 292,592 293,816 292,592 292,592 292,592 2005 295,634 297,218 295,634 295,634 295,634 2006 298,106 300,427 298,106 298,106 298,106 2007 301,533 304,989 301,533 301,533 301,533 2008 304,137 308,870 304,137 304,137 304,137 2009 305,903 312,092 305,903 305,903 305,903 2010 308,579 315,854 307,082 308,579 308,579 2011 311,230 319,606 308,190 311,033 311,033 2012 313,865 323,359 309,241 313,752 313,744 2013 316,489 327,120 310,246 316,295 316,270 2014 319,109 330,897 311,216 318,897 318,847 2015 321,737 334,700 312,170 321,544 321,461 2016 324,380 338,537 313,121 324,333 324,210 2017 327,038 342,400 314,075 327,391 327,221 2018 329,704 346,279 315,034 330,733 330,509 2019 332,373 350,163 316,001 334,264 333,977 2020 335,038 354,041 316,975 338,159 337,804 2021 337,693 357,906 317,957 342,367 341,933 2022 340,332 361,751 318,944 346,742 346,223 2023 342,950 365,569 319,934 351,034 350,430 2024 345,541 369,359 320,922 355,306 354,619 2025 348,101 373,115 321,900 359,651 358,879 2026 350,626 376,837 322,863 363,968 363,111 2027 353,110 380,521 323,799 368,153 367,212 2028 355,549 384,164 324,699 372,341 371,317 2029 357,939 387,762 325,553 376,521 375,414 2030 360,277 391,313 326,354 380,791 379,601 2031 362,563 394,819 327,098 385,088 383,814 Edge Analytics Ltd 8
Corby Population Forecasts Corby - Population growth - Natural Change Emerging Approach A & B 2001 53,407 53,407 53,407 53,407 2002 53,239 53,217 53,239 53,239 2003 53,082 53,065 53,082 53,082 2004 53,069 53,268 53,069 53,069 2005 53,521 53,929 53,521 53,521 2006 53,536 54,400 53,536 53,536 2007 54,008 55,560 54,008 54,008 2008 54,504 56,751 54,504 54,504 2009 55,172 58,070 55,172 55,172 2010 55,591 59,091 55,435 55,591 2011 56,013 60,131 55,695 56,898 2012 56,440 61,189 55,954 58,268 2013 56,870 62,266 56,213 59,630 2014 57,306 63,360 56,472 61,017 2015 57,747 64,474 56,734 62,417 2016 58,195 65,606 56,999 63,851 2017 58,648 66,752 57,267 65,309 2018 59,104 67,910 57,537 66,821 2019 59,560 69,075 57,807 68,411 2020 60,013 70,242 58,075 70,063 2021 60,460 71,408 58,341 71,844 2022 60,901 72,571 58,603 73,559 2023 61,333 73,728 58,860 75,281 2024 61,756 74,880 59,113 76,993 2025 62,170 76,025 59,360 78,722 2026 62,577 77,166 59,602 80,425 2027 62,975 78,301 59,838 82,102 2028 63,367 79,433 60,067 83,778 2029 63,751 80,561 60,288 85,496 2030 64,129 81,687 60,500 87,220 2031 64,503 82,813 60,705 88,905 Edge Analytics Ltd 9
Four Towns Population Forecasts Four Towns - Population growth - Natural Change Emerging Approach A & B 2001 51,623 51,623 51,623 51,623 2002 52,609 52,925 52,609 52,609 2003 53,862 54,256 53,862 53,862 2004 54,527 55,024 54,527 54,527 2005 55,045 55,606 55,045 55,045 2006 56,033 56,729 56,033 56,033 2007 56,858 57,689 56,858 56,858 2008 57,157 58,068 57,157 57,157 2009 57,312 58,326 57,312 57,312 2010 57,864 58,988 57,500 57,864 2011 58,407 59,640 57,676 58,174 2012 58,942 60,285 57,840 58,385 2013 59,470 60,923 57,995 58,563 2014 59,993 61,560 58,144 58,717 2015 60,512 62,195 58,289 58,908 2016 61,031 62,833 58,435 59,074 2017 61,550 63,472 58,584 59,378 2018 62,068 64,109 58,736 59,753 2019 62,584 64,743 58,892 60,191 2020 63,099 65,371 59,053 60,708 2021 63,612 65,994 59,220 61,305 2022 64,123 66,610 59,393 62,002 2023 64,631 67,219 59,570 62,629 2024 65,135 67,820 59,751 63,230 2025 65,633 68,412 59,933 63,828 2026 66,125 68,996 60,114 64,470 2027 66,609 69,570 60,292 65,153 2028 67,084 70,133 60,464 65,776 2029 67,547 70,683 60,625 66,395 2030 67,997 71,219 60,774 67,031 2031 68,434 71,742 60,912 67,705 Edge Analytics Ltd 10
Rural North, Oundle, and Thrapston Population Forecasts Rural North, Oundle and Thrapston - Population growth - Natural Change Emerging Approach A & B 2001 25,212 25,212 25,212 25,212 2002 25,410 25,549 25,410 25,410 2003 25,899 26,029 25,899 25,899 2004 26,176 26,305 26,176 26,176 2005 26,561 26,701 26,561 26,561 2006 26,785 26,944 26,785 26,785 2007 27,210 27,422 27,210 27,210 2008 27,557 27,801 27,557 27,557 2009 27,680 27,948 27,680 27,680 2010 27,982 28,278 27,707 27,982 2011 28,279 28,603 27,727 28,057 2012 28,572 28,922 27,741 28,231 2013 28,861 29,236 27,751 28,368 2014 29,145 29,546 27,758 28,490 2015 29,428 29,854 27,767 28,555 2016 29,708 30,161 27,779 28,619 2017 29,987 30,466 27,795 28,698 2018 30,265 30,770 27,818 28,768 2019 30,543 31,072 27,848 28,825 2020 30,821 31,372 27,886 28,909 2021 31,099 31,671 27,932 28,996 2022 31,376 31,967 27,985 29,084 2023 31,653 32,260 28,044 29,149 2024 31,928 32,550 28,106 29,228 2025 32,201 32,837 28,170 29,311 2026 32,471 33,120 28,233 29,385 2027 32,738 33,399 28,292 29,468 2028 33,001 33,673 28,344 29,535 2029 33,259 33,942 28,388 29,605 2030 33,511 34,204 28,422 29,690 2031 33,756 34,460 28,444 29,778 Edge Analytics Ltd 11
Kettering Population Forecasts Kettering - Population growth - Natural Change Emerging Approach A & B 2001 61,255 61,255 61,255 61,255 2002 61,745 62,072 61,745 61,745 2003 62,519 62,955 62,519 62,519 2004 62,824 63,386 62,824 62,824 2005 63,266 63,954 63,266 63,266 2006 63,663 64,529 63,663 63,663 2007 64,323 65,363 64,323 64,323 2008 64,676 65,903 64,676 64,676 2009 65,212 66,663 65,212 65,212 2010 65,688 67,333 65,484 65,688 2011 66,159 67,998 65,743 66,005 2012 66,627 68,662 65,991 66,415 2013 67,096 69,327 66,230 66,763 2014 67,565 69,994 66,461 67,196 2015 68,039 70,666 66,689 67,630 2016 68,518 71,345 66,914 68,138 2017 69,004 72,029 67,137 68,731 2018 69,495 72,718 67,359 69,369 2019 69,990 73,410 67,579 70,056 2020 70,488 74,103 67,798 70,860 2021 70,987 74,796 68,014 71,656 2022 71,486 75,489 68,228 72,590 2023 71,983 76,179 68,439 73,493 2024 72,477 76,866 68,649 74,410 2025 72,966 77,548 68,855 75,327 2026 73,449 78,223 69,057 76,181 2027 73,924 78,892 69,254 77,002 2028 74,390 79,553 69,446 77,876 2029 74,847 80,205 69,632 78,711 2030 75,294 80,849 69,812 79,557 2031 75,731 81,483 69,983 80,471 Edge Analytics Ltd 12
Rothwell and Desborough Population Forecasts Rothwell and Desborough - Population growth - Natural Change Emerging Approach A & B 2001 21,049 21,049 21,049 21,049 2002 21,311 21,429 21,311 21,311 2003 21,775 21,925 21,775 21,775 2004 22,370 22,573 22,370 22,370 2005 22,721 22,967 22,721 22,721 2006 23,182 23,501 23,182 23,182 2007 23,973 24,376 23,973 23,973 2008 24,670 25,138 24,670 24,670 2009 24,871 25,422 24,871 24,871 2010 25,394 26,020 24,984 25,394 2011 25,916 26,616 25,084 25,974 2012 26,437 27,213 25,173 26,488 2013 26,957 27,809 25,253 26,951 2014 27,478 28,407 25,325 27,337 2015 28,000 29,005 25,393 27,654 2016 28,524 29,606 25,456 27,970 2017 29,050 30,208 25,518 28,224 2018 29,576 30,811 25,577 28,460 2019 30,105 31,416 25,637 28,634 2020 30,634 32,020 25,696 28,825 2021 31,164 32,626 25,757 29,011 2022 31,695 33,232 25,819 29,099 2023 32,227 33,839 25,882 29,223 2024 32,760 34,447 25,947 29,339 2025 33,294 35,056 26,013 29,464 2026 33,829 35,665 26,080 29,568 2027 34,364 36,276 26,146 29,625 2028 34,899 36,886 26,210 29,724 2029 35,433 37,497 26,271 29,799 2030 35,967 38,107 26,330 29,902 2031 36,500 38,716 26,384 29,978 Edge Analytics Ltd 13
Wellingborough Population Forecasts Wellingborough - Population growth - Natural Change Emerging Approach A Emerging Approach B 2001 72,547 72,547 72,547 72,547 72,547 2002 73,163 72,848 73,163 73,163 73,163 2003 73,260 72,957 73,260 73,260 73,260 2004 73,626 73,260 73,626 73,626 73,626 2005 74,520 74,061 74,520 74,520 74,520 2006 74,907 74,324 74,907 74,907 74,907 2007 75,161 74,579 75,161 75,161 75,161 2008 75,573 75,209 75,573 75,573 75,573 2009 75,656 75,663 75,656 75,656 75,656 2010 76,059 76,144 75,971 76,059 76,059 2011 76,456 76,618 76,266 75,925 75,925 2012 76,847 77,089 76,543 75,964 75,956 2013 77,236 77,559 76,805 76,020 75,994 2014 77,622 78,030 77,055 76,141 76,091 2015 78,011 78,505 77,298 76,380 76,297 2016 78,403 78,986 77,537 76,681 76,557 2017 78,799 79,473 77,773 77,050 76,881 2018 79,195 79,961 78,007 77,561 77,336 2019 79,590 80,448 78,238 78,147 77,860 2020 79,983 80,933 78,467 78,794 78,439 2021 80,370 81,411 78,694 79,556 79,123 2022 80,751 81,882 78,918 80,407 79,888 2023 81,124 82,344 79,139 81,260 80,656 2024 81,486 82,796 79,356 82,107 81,419 2025 81,837 83,237 79,569 82,999 82,227 2026 82,175 83,667 79,777 83,939 83,082 2027 82,499 84,083 79,977 84,803 83,863 2028 82,808 84,486 80,168 85,651 84,627 2029 83,102 84,874 80,349 86,515 85,408 2030 83,378 85,247 80,517 87,391 86,201 2031 83,638 85,604 80,671 88,251 86,978 Edge Analytics Ltd 14
2.3 Household scenario summaries This section provides an illustration of the implications of the population forecasts upon household numbers. Household numbers are derived (using the Derived Forecast model) through the application of household headship rates to the age-sex profile of the population. They differ from dwelling numbers in that they take account of vacancy rates applicable to each area (see Appendix for a definition of these). North Northamptonshire Household forecasts North Northamptonshire - Household forecast - Natural Change Emerging Approach A Emerging Approach B 2001 117,771 117,771 117,771 117,771 117,771 2002 119,486 119,588 119,486 119,486 119,486 2003 121,035 121,264 121,035 121,035 121,035 2004 122,107 122,482 122,107 122,107 122,107 2005 123,712 124,170 123,712 123,712 123,712 2006 125,043 125,785 125,043 125,043 125,043 2007 126,483 127,875 126,483 126,483 126,483 2008 127,754 129,896 127,754 127,754 127,754 2009 128,731 131,598 128,731 128,731 128,731 2010 130,105 133,639 129,230 130,105 130,105 2011 131,520 135,665 129,765 131,446 131,446 2012 132,902 137,577 130,280 132,864 132,861 2013 134,419 139,590 130,952 134,360 134,350 2014 135,987 141,653 131,686 135,935 135,916 2015 137,615 143,628 132,539 137,589 137,557 2016 139,274 145,722 133,465 139,321 139,272 2017 140,915 147,850 134,406 141,130 141,063 2018 142,524 150,018 135,304 143,018 142,928 2019 144,141 152,187 136,199 144,982 144,868 2020 145,693 154,338 137,029 147,027 146,884 2021 147,197 156,429 137,788 149,149 148,974 2022 148,694 158,506 138,531 151,349 151,139 2023 150,212 160,612 139,282 153,549 153,303 2024 151,722 162,726 140,004 155,748 155,468 2025 153,188 164,779 140,715 157,948 157,633 2026 154,651 166,803 141,434 160,148 159,797 2027 156,153 168,842 142,200 162,348 161,962 2028 157,634 170,847 142,956 164,547 164,127 2029 159,102 172,866 143,725 166,747 166,291 2030 160,513 174,818 144,407 168,947 168,456 2031 161,893 176,763 145,044 171,146 170,621 Edge Analytics Ltd 15
Corby - Household forecast Corby Household forecasts - Natural Change Emerging Approach A & B 2001 21,790 21,790 21,790 21,790 2002 21,886 21,850 21,886 21,886 2003 21,952 21,912 21,952 21,952 2004 22,009 22,053 22,009 22,009 2005 22,237 22,368 22,237 22,237 2006 22,326 22,616 22,326 22,326 2007 22,506 23,085 22,506 22,506 2008 22,716 23,606 22,716 22,716 2009 22,985 24,149 22,985 22,985 2010 23,206 24,643 23,126 23,206 2011 23,442 25,150 23,274 23,775 2012 23,665 25,635 23,405 24,357 2013 23,896 26,134 23,537 24,955 2014 24,126 26,651 23,662 25,568 2015 24,360 27,156 23,803 26,195 2016 24,594 27,677 23,962 26,837 2017 24,834 28,220 24,138 27,494 2018 25,068 28,772 24,308 28,165 2019 25,290 29,304 24,470 28,851 2020 25,504 29,844 24,621 29,552 2021 25,687 30,349 24,735 30,268 2022 25,896 30,886 24,879 30,999 2023 26,102 31,420 25,011 31,729 2024 26,306 31,959 25,136 32,460 2025 26,498 32,479 25,257 33,190 2026 26,700 33,006 25,395 33,921 2027 26,909 33,535 25,546 34,651 2028 27,113 34,054 25,691 35,382 2029 27,299 34,562 25,821 36,112 2030 27,481 35,072 25,943 36,843 2031 27,672 35,600 26,070 37,573 Four Towns - Household forecast Four Towns Household forecasts - Natural Change Emerging Approach A & B 2001 21,268 21,268 21,268 21,268 2002 21,791 21,884 21,791 21,791 2003 22,334 22,467 22,334 22,334 2004 22,642 22,789 22,642 22,642 2005 22,919 23,066 22,919 22,919 2006 23,354 23,538 23,354 23,354 2007 23,670 23,978 23,670 23,670 2008 23,830 24,267 23,830 23,830 2009 23,925 24,496 23,925 23,925 2010 24,156 24,867 23,913 24,156 2011 24,404 25,239 23,929 24,316 2012 24,662 25,575 23,970 24,453 2013 24,953 25,930 24,068 24,612 2014 25,273 26,303 24,217 24,792 2015 25,601 26,627 24,374 24,994 2016 25,964 27,015 24,574 25,217 2017 26,297 27,386 24,742 25,462 2018 26,625 27,776 24,908 25,729 2019 26,949 28,162 25,071 26,017 2020 27,264 28,548 25,230 26,326 2021 27,567 28,920 25,373 26,657 2022 27,850 29,264 25,492 27,011 2023 28,159 29,632 25,635 27,364 2024 28,475 30,009 25,786 27,717 2025 28,789 30,387 25,941 28,070 2026 29,083 30,734 26,068 28,423 2027 29,358 31,049 26,174 28,776 2028 29,653 31,389 26,301 29,129 2029 29,946 31,735 26,430 29,482 2030 30,228 32,068 26,545 29,835 2031 30,491 32,382 26,636 30,189 Edge Analytics Ltd 16
Rural North, Oundle and Thrapston Household forecasts Rural North, Oundle and Thrapston - Household forecast - Natural Change Emerging Approach A & B 2001 10,093 10,093 10,093 10,093 2002 10,244 10,289 10,244 10,244 2003 10,426 10,485 10,426 10,426 2004 10,534 10,599 10,534 10,534 2005 10,681 10,754 10,681 10,681 2006 10,801 10,892 10,801 10,801 2007 10,958 11,099 10,958 10,958 2008 11,112 11,292 11,112 11,112 2009 11,201 11,419 11,201 11,201 2010 11,337 11,590 11,190 11,337 2011 11,464 11,749 11,173 11,384 2012 11,598 11,907 11,171 11,476 2013 11,743 12,074 11,207 11,566 2014 11,893 12,240 11,278 11,657 2015 12,063 12,402 11,385 11,746 2016 12,232 12,572 11,486 11,835 2017 12,397 12,743 11,594 11,923 2018 12,564 12,923 11,696 12,010 2019 12,736 13,110 11,802 12,095 2020 12,898 13,289 11,893 12,181 2021 13,058 13,465 11,971 12,266 2022 13,218 13,641 12,039 12,350 2023 13,388 13,826 12,115 12,434 2024 13,552 14,005 12,177 12,518 2025 13,713 14,177 12,231 12,602 2026 13,878 14,352 12,288 12,685 2027 14,038 14,519 12,336 12,769 2028 14,205 14,694 12,388 12,853 2029 14,370 14,869 12,440 12,937 2030 14,526 15,034 12,476 13,021 2031 14,679 15,198 12,501 13,105 Kettering - Household forecast Kettering Household forecasts - Natural Change Emerging Approach A & B 2001 25,814 25,814 25,814 25,814 2002 26,104 26,191 26,104 26,104 2003 26,512 26,647 26,512 26,512 2004 26,688 26,868 26,688 26,688 2005 26,948 27,169 26,948 26,948 2006 27,151 27,466 27,151 27,151 2007 27,455 27,874 27,455 27,455 2008 27,651 28,210 27,651 27,651 2009 27,934 28,599 27,934 27,934 2010 28,179 28,963 28,050 28,179 2011 28,445 29,337 28,184 28,388 2012 28,698 29,696 28,300 28,619 2013 28,999 30,089 28,457 28,874 2014 29,292 30,473 28,597 29,151 2015 29,609 30,862 28,769 29,451 2016 29,923 31,259 28,948 29,773 2017 30,229 31,650 29,120 30,117 2018 30,541 32,064 29,296 30,485 2019 30,857 32,480 29,474 30,874 2020 31,151 32,877 29,630 31,287 2021 31,466 33,303 29,807 31,722 2022 31,749 33,692 29,953 32,179 2023 32,041 34,088 30,105 32,637 2024 32,326 34,475 30,248 33,094 2025 32,606 34,862 30,393 33,551 2026 32,907 35,260 30,564 34,008 2027 33,217 35,669 30,748 34,465 2028 33,504 36,050 30,911 34,923 2029 33,801 36,446 31,086 35,380 2030 34,091 36,830 31,253 35,837 2031 34,351 37,189 31,394 36,294 Edge Analytics Ltd 17
Rothwell and Desborough Household forecasts Rothwell and Desborough - Household forecast - Natural Change Emerging Approach A & B 2001 8,679 8,679 8,679 8,679 2002 8,826 8,859 8,826 8,826 2003 9,034 9,083 9,034 9,034 2004 9,286 9,357 9,286 9,286 2005 9,492 9,578 9,492 9,492 2006 9,726 9,848 9,726 9,726 2007 10,043 10,209 10,043 10,043 2008 10,357 10,570 10,357 10,357 2009 10,462 10,713 10,462 10,462 2010 10,709 11,004 10,511 10,709 2011 10,936 11,269 10,541 10,958 2012 11,171 11,543 10,586 11,190 2013 11,410 11,814 10,633 11,408 2014 11,662 12,102 10,683 11,609 2015 11,927 12,394 10,750 11,795 2016 12,178 12,678 10,805 11,967 2017 12,440 12,973 10,873 12,123 2018 12,696 13,268 10,928 12,263 2019 12,962 13,571 10,985 12,388 2020 13,207 13,855 11,025 12,498 2021 13,438 14,123 11,055 12,592 2022 13,694 14,420 11,112 12,670 2023 13,937 14,702 11,157 12,749 2024 14,183 14,987 11,202 12,827 2025 14,426 15,269 11,248 12,906 2026 14,678 15,557 11,301 12,984 2027 14,952 15,869 11,373 13,063 2028 15,207 16,157 11,428 13,141 2029 15,476 16,464 11,505 13,220 2030 15,730 16,752 11,558 13,298 2031 15,996 17,055 11,614 13,377 Wellingborough Household forecasts Wellingborough - Household forecast - Natural Change Emerging Approach A Emerging Approach B 2001 30,128 30,128 30,128 30,128 30,128 2002 30,635 30,515 30,635 30,635 30,635 2003 30,777 30,670 30,777 30,777 30,777 2004 30,948 30,816 30,948 30,948 30,948 2005 31,435 31,235 31,435 31,435 31,435 2006 31,685 31,425 31,685 31,685 31,685 2007 31,852 31,630 31,852 31,852 31,852 2008 32,088 31,952 32,088 32,088 32,088 2009 32,223 32,220 32,223 32,223 32,223 2010 32,518 32,573 32,441 32,518 32,518 2011 32,829 32,921 32,664 32,626 32,626 2012 33,108 33,220 32,847 32,768 32,765 2013 33,418 33,549 33,050 32,946 32,936 2014 33,741 33,884 33,250 33,159 33,140 2015 34,056 34,187 33,458 33,407 33,375 2016 34,382 34,521 33,691 33,692 33,643 2017 34,718 34,878 33,939 34,011 33,944 2018 35,031 35,214 34,168 34,366 34,277 2019 35,348 35,559 34,397 34,757 34,642 2020 35,671 35,924 34,630 35,182 35,039 2021 35,981 36,269 34,847 35,643 35,468 2022 36,285 36,604 35,056 36,140 35,930 2023 36,584 36,945 35,259 36,636 36,391 2024 36,881 37,291 35,455 37,133 36,852 2025 37,155 37,604 35,644 37,629 37,314 2026 37,405 37,893 35,818 38,126 37,775 2027 37,679 38,201 36,023 38,622 38,237 2028 37,951 38,503 36,236 39,119 38,698 2029 38,210 38,790 36,443 39,615 39,160 2030 38,457 39,061 36,633 40,112 39,621 2031 38,704 39,338 36,829 40,608 40,083 Edge Analytics Ltd 18
2.4 Labour force scenario summaries Using the Derived Forecast model, it is possible to examine the effect of alternative population forecasts upon the size of the labour force in each district. This is achieved through the application of economic activity rates (by age and sex) to the population of each area. Economic activity rates (averaged 2004-2009) have been derived from NOMIS (see Appendix). The tables below illustrate the size of the labour force that would result from the alternative population forecasts, keeping economic activity rates constant throughout the forecast period. North Northamptonshire Labour Force forecasts North Northamptonshire - Labour force forecast - Natural Change Emerging Approach A Emerging Approach B 2011 165,387 170,815 163,501 165,274 165,274 2012 165,649 171,718 162,864 165,597 165,592 2013 166,012 172,755 162,335 165,921 165,905 2014 166,555 173,988 161,992 166,464 166,432 2015 167,082 175,198 161,629 167,010 166,958 2016 167,694 176,510 161,353 167,720 167,642 2017 168,281 177,805 161,060 168,557 168,451 2018 168,885 179,073 160,787 169,573 169,434 2019 169,394 180,224 160,415 170,599 170,423 2020 170,192 181,664 160,325 172,130 171,912 2021 170,889 182,977 160,131 173,749 173,485 2022 171,649 184,336 159,988 175,530 175,216 2023 172,442 185,739 159,846 177,292 176,930 2024 173,394 187,287 159,855 179,206 178,795 2025 174,278 188,732 159,775 181,104 180,646 2026 174,907 190,008 159,431 182,720 182,216 2027 175,596 191,358 159,112 184,322 183,772 2028 176,170 192,595 158,661 185,835 185,239 2029 176,602 193,690 158,072 187,228 186,589 2030 176,754 194,580 157,235 188,417 187,733 2031 176,870 195,348 156,367 189,606 188,878 Edge Analytics Ltd 19
Corby - Labour force forecast Corby Labour Force forecasts - Natural Change Emerging Approach A & B 2011 29,731 32,486 29,552 30,284 2012 29,773 32,912 29,515 30,907 2013 29,847 33,379 29,510 31,546 2014 29,949 33,878 29,535 32,216 2015 29,991 34,322 29,499 32,819 2016 30,045 34,776 29,473 33,441 2017 30,111 35,246 29,464 34,078 2018 30,138 35,672 29,412 34,694 2019 30,137 36,066 29,330 35,317 2020 30,186 36,520 29,301 36,025 2021 30,237 36,969 29,272 36,807 2022 30,317 37,434 29,265 37,572 2023 30,411 37,917 29,266 38,355 2024 30,563 38,461 29,319 39,194 2025 30,723 39,004 29,367 40,056 2026 30,787 39,481 29,325 40,792 2027 30,888 40,016 29,313 41,552 2028 30,975 40,527 29,280 42,308 2029 31,078 41,049 29,263 43,117 2030 31,138 41,538 29,199 43,884 2031 31,198 42,031 29,134 44,629 Four Towns Labour Force forecasts Four Towns - Labour force forecast - Natural Change Emerging Approach A & B 2011 30,981 31,970 30,632 30,844 2012 31,049 32,098 30,528 30,723 2013 31,113 32,240 30,420 30,582 2014 31,199 32,407 30,335 30,455 2015 31,322 32,602 30,279 30,389 2016 31,457 32,817 30,236 30,324 2017 31,534 32,974 30,137 30,284 2018 31,657 33,159 30,087 30,335 2019 31,779 33,336 30,037 30,423 2020 31,972 33,590 30,059 30,630 2021 32,150 33,827 30,061 30,870 2022 32,270 34,002 30,009 31,113 2023 32,437 34,221 29,992 31,361 2024 32,649 34,474 30,024 31,638 2025 32,852 34,705 30,042 31,905 2026 32,999 34,896 29,995 32,143 2027 33,156 35,100 29,958 32,416 2028 33,268 35,266 29,865 32,613 2029 33,351 35,417 29,753 32,782 2030 33,345 35,496 29,553 32,877 2031 33,301 35,507 29,322 32,961 Edge Analytics Ltd 20
Rural North, Oundle and Thrapston Labour Force forecasts Rural North, Oundle and Thrapston - Labour force forecast - Natural Change Emerging Approach A & B 2011 14,566 14,809 14,424 14,438 2012 14,612 14,857 14,392 14,414 2013 14,656 14,918 14,353 14,370 2014 14,725 15,004 14,333 14,343 2015 14,800 15,094 14,310 14,293 2016 14,864 15,176 14,271 14,231 2017 14,959 15,290 14,254 14,211 2018 15,017 15,354 14,199 14,150 2019 15,068 15,407 14,128 14,075 2020 15,153 15,498 14,078 14,050 2021 15,234 15,584 14,024 14,024 2022 15,316 15,670 13,966 14,002 2023 15,387 15,745 13,887 13,957 2024 15,488 15,843 13,829 13,948 2025 15,557 15,904 13,740 13,914 2026 15,619 15,963 13,633 13,868 2027 15,676 16,017 13,517 13,824 2028 15,702 16,040 13,373 13,745 2029 15,717 16,061 13,216 13,659 2030 15,689 16,052 13,042 13,546 2031 15,666 16,026 12,883 13,445 Kettering Labour Force forecasts Kettering - Labour force forecast - Natural Change Emerging Approach A & B 2011 35,289 36,456 34,929 35,193 2012 35,310 36,605 34,785 35,180 2013 35,341 36,764 34,659 35,137 2014 35,403 36,950 34,567 35,179 2015 35,489 37,160 34,502 35,244 2016 35,626 37,425 34,488 35,401 2017 35,778 37,701 34,488 35,623 2018 35,946 37,985 34,502 35,885 2019 36,074 38,232 34,474 36,133 2020 36,252 38,520 34,498 36,500 2021 36,417 38,784 34,514 36,846 2022 36,575 39,038 34,519 37,268 2023 36,710 39,279 34,507 37,645 2024 36,878 39,551 34,530 38,062 2025 37,027 39,797 34,538 38,459 2026 37,149 40,035 34,518 38,790 2027 37,239 40,234 34,460 39,069 2028 37,335 40,437 34,406 39,389 2029 37,399 40,593 34,310 39,658 2030 37,411 40,714 34,168 39,881 2031 37,436 40,831 34,037 40,167 Edge Analytics Ltd 21
Rothwell and Desborough Labour Force forecasts Rothwell and Desborough - Labour force forecast - Natural Change Emerging Approach A & B 2011 13,920 14,362 13,387 13,956 2012 14,076 14,565 13,280 14,107 2013 14,250 14,788 13,190 14,245 2014 14,425 15,011 13,101 14,339 2015 14,575 15,206 12,993 14,364 2016 14,740 15,419 12,904 14,405 2017 14,916 15,641 12,834 14,418 2018 15,114 15,881 12,788 14,444 2019 15,312 16,124 12,748 14,435 2020 15,552 16,405 12,745 14,479 2021 15,762 16,650 12,710 14,493 2022 15,992 16,915 12,692 14,471 2023 16,246 17,210 12,687 14,495 2024 16,475 17,477 12,657 14,493 2025 16,712 17,750 12,629 14,507 2026 16,936 18,016 12,592 14,496 2027 17,196 18,318 12,580 14,491 2028 17,430 18,591 12,541 14,489 2029 17,625 18,818 12,472 14,437 2030 17,807 19,042 12,392 14,393 2031 17,996 19,264 12,312 14,340 Wellingborough Labour Force forecasts Wellingborough - Labour force forecast - Natural Change Emerging Approach A Emerging Approach B 2011 40,900 40,733 40,577 40,558 40,558 2012 40,828 40,681 40,363 40,267 40,262 2013 40,805 40,666 40,204 40,040 40,024 2014 40,854 40,738 40,122 39,931 39,899 2015 40,904 40,814 40,046 39,900 39,848 2016 40,962 40,897 39,981 39,918 39,840 2017 40,983 40,954 39,883 39,942 39,837 2018 41,014 41,023 39,798 40,066 39,927 2019 41,024 41,059 39,697 40,216 40,039 2020 41,077 41,132 39,645 40,446 40,228 2021 41,089 41,163 39,551 40,709 40,445 2022 41,178 41,275 39,537 41,103 40,789 2023 41,251 41,367 39,507 41,481 41,118 2024 41,342 41,480 39,497 41,872 41,461 2025 41,406 41,571 39,458 42,264 41,806 2026 41,417 41,616 39,369 42,632 42,128 2027 41,442 41,674 39,284 42,969 42,419 2028 41,460 41,734 39,195 43,290 42,695 2029 41,431 41,751 39,058 43,575 42,936 2030 41,364 41,737 38,882 43,834 43,151 2031 41,272 41,689 38,679 44,063 43,336 Edge Analytics Ltd 22
Rate per 1,000 population 3 Appendix: Data Inputs and assumptions The POPGROUP model draws data from a number of sources, building an historical picture of population, households, fertility, mortality and migration on which to base its scenario forecasts. Using the historical data evidence for 2001-2009, in conjunction with information from ONS national projections, a series of assumptions have been derived which drive the scenario forecasts. These assumptions are used when historical data or constraints on fertility, mortality, migration and population are not available. 3.1 Population The forecasting process uses the following population data as historical constraints: Mid 2001 to mid 2009 population by age and sex. The data includes the revised 2002-2008 mid-year estimates released by ONS in 2010, and the 2009- mid-year estimates released a little later. 3.2 Births and fertility The forecasting process uses the following birth and fertility information: Mid-year counts of births by sex, 2001 2009. Standard age-specific fertility schedule from national projections are combined with local evidence on births, to produce age-specific fertility rates for each area within North Northamptonshire (see below). North Northamptonshire JPU - Small Area Forecasts Fertility Age schedule of rates per 1,000 women (from the schedule and 1st year differentials only; counts and TFR will take effect when used in a forecast) 160 140 120 100 80 60 1 Corby 2 Four T 3 RNOT 4 Ktring 5 R-Des 6 Wbrgh 40 20 0 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 Age The trend in fertility for each year of the forecast follows that set by ONS in its national 2008-based population projection assumptions. Following the rise in fertility since 2001, these national assumptions assume a decline from 2009. Edge Analytics Ltd 23
Rate per 1,000 population Total fertility Rate (TFR) 2008-based 2.00 1.95 1.90 1.85 1.80 1.75 1.70 1.65 1.60 2008 2012 2016 2020 2024 2028 2032 3.3 Deaths and mortality The forecasting process uses the following death and mortality information: Mid-year counts of deaths 2001 2009. Deaths by age and sex from 2001 2009. Standard age-specific mortality schedule from national projections are combined with local evidence on deaths, to produce age-specific mortality rates for each area within North Northamptonshire (see below). North Northamptonshire JPU - Small Area Forecasts Mortality Age schedule of rates per 1,000 Males (from the schedule and 1st year differentials only; counts and SMR will take effect when used in a forecast) 300 250 200 150 100 50 0 Newborn 2 5 8 11 14 17 20 23 26 29 32 35 38 41 44 Age 47 50 53 56 59 62 65 68 71 74 77 80 83 86 89 1 Corby 2 Four T 3 RNOT 4 Ktring 5 R-Des 6 Wbrgh Future trends The trend in mortality for each year of the forecast (at district level) follows that set by ONS in its national 2008-based population projection assumptions. Mortality rates continue to decline throughout the projection period (see below). Edge Analytics Ltd 24
Standardised Mortality Ratio (SMR) 2008-based 110.0 105.0 100.0 95.0 90.0 85.0 80.0 75.0 70.0 2008 2012 2016 2020 2024 2028 2032 Different assumptions are applied to the male and female schedules of mortality decline. 3.4 Migration Migration is typically the most difficult component to measure. The forecasting process uses the following migration statistics: For districts, internal migration data by age and sex is drawn from patient registration statistics. The 2008-based projections include the revisions resulting from ONS new estimation methodology, with new registration statistics produced for 2002-2008. Mid-year population estimates provide assumptions for international migration on immigration and emigration flows by district. For sub-districts, historical migration estimates have been derived as a residual after having taken account of births and deaths in the change in population between successive years. For sub-district areas there is no distinction made between internal and international migration, with total net migration used as the key migration assumption. Assumptions about the future impact of migration within each area have been derived using historical evidence from the last five years (2004/5 2008/9). 3.5 Households The household projection methodology used by POPGROUP is that employed by CLG, applying headship rates by household type to population forecasts by age and sex. This produces a household forecast by household type, age and sex. Household forecasts for North Northamptonshire have been made using the latest CLG 2008-based projections from November 2010 which provide information on: Households by household type Population not in households Headship rates by household type, age and sex These are 2008-based and are used in all scenarios. Edge Analytics Ltd 25
The household types as defined by the CLG 2008 household projections and used by the Derived Forecast Model are as follows: 1. One person households: Male 2. One person households: Female 3. One family and no others: Couple: No dependent children 4. One family and no others: Couple: 1 dependent child 5. One family and no others: Couple: 2 dependent children 6. One family and no others: Couple: 3+ dependent children 7. One family and no others: Lone parent: 1 dependent child 8. One family and no others: Lone parent: 2 dependent children 9. One family and no others: Lone parent: 3+ dependent children 10. A couple and one or more other adults: No dependent children 11. A couple and one or more other adults: 1 dependent child 12. A couple and one or more other adults: 2 dependent children 13. A couple and one or more other adults: 3+ dependent children 14. A lone parent and one or more other adults: 1 dependent child 15. A lone parent and one or more other adults: 2 dependent children 16. A lone parent and one or more other adults: 3+ dependent children 17. Other households For sub-district areas, headship rates have been calibrated to ensure district rates are modified to account for local variation in household type and household formation rates. 3.6 Dwellings The Derived Forecast model uses a vacancy rate to convert households into dwellings. These vacancy rates have been derived from 2001 Census data and are maintained at a constant level in the scenario forecasts. Users may vary them to evaluate alternative scenarios. The vacancy rate data by district and areas area as follows: Area 2001 Vacancy rate Corby 97.1% Four T 96.2% RNOT 95.3% Ktring 96.5% R-Des 96.9% Wellingborough 97.4% Source: Census 2001 To run the Emerging Approach dwelling-led scenarios, NNJPU provided forecast dwelling numbers as follows: Edge Analytics Ltd 26
Dwelling growth Corby Four Towns RNOT Kettering R & D Wellingborough A Wellingborough B 2011-12 600 142 96 240 240 146 143 2012-13 615 165 95 264 224 183 176 2013-14 631 187 95 287 208 219 209 2014-15 646 210 94 311 192 255 242 2015-16 661 232 93 334 177 292 275 2016-17 676 255 92 357 161 328 309 2017-18 691 277 91 381 145 365 342 2018-19 706 299 90 404 129 401 375 2019-20 722 322 90 428 113 437 408 2020-21 737 344 89 451 97 474 441 2021-22 752 367 88 474 81 510 474 2022-23 752 367 88 474 81 510 474 2023-24 752 367 88 474 81 510 474 2024-25 752 367 88 474 81 510 474 2025-26 752 367 88 474 81 510 474 2026-27 752 367 88 474 81 510 474 2027-28 752 367 88 474 81 510 474 2028-29 752 367 88 474 81 510 474 2029-30 752 367 88 474 81 510 474 2030-31 752 367 88 474 81 510 474 TOTAL 14,205 6,103 1,805 8,196 2,500 8,200 7,660 Source: North Northamptonshire Joint Planning Unit Edge Analytics Ltd 27
For direct comparison with the dwelling-led scenarios, the dwelling requirements which result from the three alternative population and household forecast are included below: migration-led, migration-led re-calibrated and the natural change scenario. scenario Corby Four Towns RNOT Kettering R-Des Wellingborough 2011/12 229 268 140 263 243 287 2012/13 238 302 152 312 246 319 2013/14 237 333 157 303 261 332 2014/15 241 341 178 329 273 323 2015/16 242 377 178 325 259 336 2016/17 247 346 172 317 270 345 2017/18 240 340 175 324 263 322 2018/19 229 337 181 328 275 325 2019/20 221 327 170 304 253 332 2020/21 189 315 169 327 238 318 2021/22 215 294 168 293 265 313 2022/23 212 321 178 303 251 307 2023/24 210 328 172 295 254 304 2024/25 197 327 170 291 251 282 2025/26 208 306 173 312 260 257 2026/27 216 285 168 321 283 281 2027/28 210 307 174 298 263 280 2028/29 191 304 173 308 277 266 2029/30 187 293 164 300 262 254 2030/31 197 273 160 270 274 254 Total 2011-31 4,356 6,324 3,372 6,123 5,221 6,037 Corby Four Towns RNOT Kettering R-Des Wellingborough 2011/12 500 349 166 372 283 307 2012/13 514 368 175 407 280 338 2013/14 532 388 174 398 297 344 2014/15 520 338 170 403 302 311 2015/16 536 403 179 412 292 343 2016/17 559 386 179 406 305 367 2017/18 568 405 189 429 304 346 2018/19 547 401 196 431 313 354 2019/20 557 401 188 412 293 375 2020/21 520 386 185 441 276 354 2021/22 552 357 184 404 307 345 2022/23 550 382 195 410 291 350 2023/24 554 392 188 402 294 356 2024/25 536 393 180 401 292 321 2025/26 542 361 184 413 297 297 2026/27 545 327 176 424 321 317 2027/28 535 354 183 394 298 310 2028/29 522 359 184 411 317 295 2029/30 525 347 173 398 297 279 2030/31 544 326 172 372 313 285 Total 2011-31 10,758 7,423 3,620 8,140 5,972 6,594 Edge Analytics Ltd 28
Natural Change Corby Four Towns RNOT Kettering R-Des Wellingborough 2011/12 135 43-2 120 47 188 2012/13 136 102 38 162 48 209 2013/14 128 155 74 145 52 205 2014/15 146 164 112 178 69 214 2015/16 164 207 105 186 56 239 2016/17 181 175 113 179 70 255 2017/18 176 173 108 182 57 234 2018/19 167 169 111 184 59 236 2019/20 155 166 96 162 41 239 2020/21 118 148 82 184 32 223 2021/22 147 123 72 152 58 215 2022/23 136 149 79 157 47 208 2023/24 129 157 65 149 46 202 2024/25 125 161 57 151 48 194 2025/26 142 131 60 177 54 178 2026/27 156 110 50 191 74 211 2027/28 149 132 55 169 58 219 2028/29 134 134 55 181 78 213 2029/30 126 120 37 172 55 195 2030/31 131 95 26 147 58 201 Total 2011-31 2,881 2,814 1,393 3,328 1,107 4,278 3.7 Labour Force Economic Activity Due to the incomplete nature of economic activity rate data for small areas, Northamptonshire economic activity rates have been used in the labour force scenarios. Northamptonshire economic activity rates were taken from the Annual Population Survey for the years 2004-2009 with the average applied in the model. Northamptonshire Males Females Economic Activity Rate (%) 2004 2005 2006 2007 2008 2009 Average 2004-2009 16-19 61.9 65.5 66.2 60.4 57.8 52.6 60.7 20-24 85.6 85.1 91.6 87.9 89.8 86.4 87.7 25-34 97.6 94.3 94.9 95.4 93.1 95.7 95.2 35-49 92.1 94.3 95.7 96.2 96.6 95.1 95.0 50-ret 81.2 80.5 81.3 83.2 84.2 86.7 82.9 Ret+ 11.2 12.4 13.7 16.5 16.6 14.0 14.1 16-19 56.0 46.7 60.8 71.6 35.3 58.5 54.8 20-24 82.2 76.6 76.4 79.5 84.3 73.2 78.7 25-34 78.3 81.8 79.1 81.5 81.0 83.3 80.8 35-49 82.2 81.9 83.6 85.5 84.2 81.9 83.2 50-ret 65.5 66.7 67.1 62.6 61.3 68.8 65.3 Ret+ 4.8 4.1 6.5 6.7 3.6 4.8 5.1 Source: NOMIS Edge Analytics Ltd 29
4 Appendix: Methodology summary Population projections use a standard cohort component methodology whilst the household projections use a standard household headship rate methodology, as employed by ONS and CLG respectively. Labour force projections are produced using an economic activity rate model. A more detailed description of the population and household projection methodologies is available from the User Guide and Reference Manual on the POPGROUP website. The mathematical calculations for each method are documented at the end of each of the manuals. www.ccsr.ac.uk/popgroup/about/manuals.html. The general population projection and household methodologies are illustrated below. Single age/sex values for each Population Group are taken from the POPBASE workbook and set to the base year of forecasts For each year of the forecast period Any Special Population age/sex data are subtracted from the previous year s forecast (or base year) for each relevant Population Group Births, deaths and migrants are calculated for each Population Group, based on age/sex values in the Population Group and the data of fertility, mortality and migration provided in the input workbooks. Births, deaths and migrants added to/ subtracted from age/sex values in the population forecasts for the previous year in each Population group TFR, SMR, Life Expectancy, SMigR are recorded on the components output workbook along with values for births, deaths and migrants If any special populations, add them back in YES Alter each Population Group s migration to meet the constraint No Population of housing constraint for forecast year? No Final year of forecast? YES Produce the output report workbooks POPGROUP Population Projection Methodology Edge Analytics Ltd 30
Population Forecast Population forecast by age and sex Derived Category Rates Rates by age and sex (e.g. headship rates, disability rates) Derived Category Forecast Forecast for Derived Categories (e.g. Households, disability) Figure 1: Derived Forecast Model - methodology Algebraically the model is defined as follows: D a,s,u,y,d,g = P a,s,u,y,g * R a,s,u,y,d,g / 100 D = P = R = Where: Derived Category Forecast Population at risk Forecast Derived Category Rates and a = s = u = y = d = g = age-group sex Sub-population year derived category group (usually an area, but can be an ethnic group or social group) Derived Forecast Projection Methodology Edge Analytics Ltd 31