Population and Household Forecasts Emerging Approach

Transcription

1 Population and Household Forecasts Emerging Approach Edge Analytics Ltd Leeds Innovations Centre 103, Clarendon Rd Leeds LS2 9DF Tel: February 2012

2 Table of Contents 1 Introduction Background Requirements POPGROUP Document structure Summary of results What has been provided? POPGROUP scenario summaries Household scenario summaries Labour force scenario summaries Appendix: Data Inputs and assumptions Population Births and fertility Deaths and mortality Migration Households Dwellings Labour Force Appendix: Methodology summary 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

3 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 Housing development plans are now outdated given the prevailing economic conditions and the judgement from the new Government that previous Regional Spatial Strategy (RSS) dwelling targets are largely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 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

4 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

5 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 , 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

6 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 ( ). It differs from the ONS official sub-national projection, which has a 2008-base and uses historical evidence from 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: 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

7 upon a re-calculated estimate of the impact of immigration since 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

8 North Northamptonshire Population Forecasts North Northamptonshire - Population growth - Natural Change Emerging Approach A Emerging Approach B , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,814 Edge Analytics Ltd 8

9 Corby Population Forecasts Corby - Population growth - Natural Change Emerging Approach A & B ,407 53,407 53,407 53, ,239 53,217 53,239 53, ,082 53,065 53,082 53, ,069 53,268 53,069 53, ,521 53,929 53,521 53, ,536 54,400 53,536 53, ,008 55,560 54,008 54, ,504 56,751 54,504 54, ,172 58,070 55,172 55, ,591 59,091 55,435 55, ,013 60,131 55,695 56, ,440 61,189 55,954 58, ,870 62,266 56,213 59, ,306 63,360 56,472 61, ,747 64,474 56,734 62, ,195 65,606 56,999 63, ,648 66,752 57,267 65, ,104 67,910 57,537 66, ,560 69,075 57,807 68, ,013 70,242 58,075 70, ,460 71,408 58,341 71, ,901 72,571 58,603 73, ,333 73,728 58,860 75, ,756 74,880 59,113 76, ,170 76,025 59,360 78, ,577 77,166 59,602 80, ,975 78,301 59,838 82, ,367 79,433 60,067 83, ,751 80,561 60,288 85, ,129 81,687 60,500 87, ,503 82,813 60,705 88,905 Edge Analytics Ltd 9

10 Four Towns Population Forecasts Four Towns - Population growth - Natural Change Emerging Approach A & B ,623 51,623 51,623 51, ,609 52,925 52,609 52, ,862 54,256 53,862 53, ,527 55,024 54,527 54, ,045 55,606 55,045 55, ,033 56,729 56,033 56, ,858 57,689 56,858 56, ,157 58,068 57,157 57, ,312 58,326 57,312 57, ,864 58,988 57,500 57, ,407 59,640 57,676 58, ,942 60,285 57,840 58, ,470 60,923 57,995 58, ,993 61,560 58,144 58, ,512 62,195 58,289 58, ,031 62,833 58,435 59, ,550 63,472 58,584 59, ,068 64,109 58,736 59, ,584 64,743 58,892 60, ,099 65,371 59,053 60, ,612 65,994 59,220 61, ,123 66,610 59,393 62, ,631 67,219 59,570 62, ,135 67,820 59,751 63, ,633 68,412 59,933 63, ,125 68,996 60,114 64, ,609 69,570 60,292 65, ,084 70,133 60,464 65, ,547 70,683 60,625 66, ,997 71,219 60,774 67, ,434 71,742 60,912 67,705 Edge Analytics Ltd 10

11 Rural North, Oundle, and Thrapston Population Forecasts Rural North, Oundle and Thrapston - Population growth - Natural Change Emerging Approach A & B ,212 25,212 25,212 25, ,410 25,549 25,410 25, ,899 26,029 25,899 25, ,176 26,305 26,176 26, ,561 26,701 26,561 26, ,785 26,944 26,785 26, ,210 27,422 27,210 27, ,557 27,801 27,557 27, ,680 27,948 27,680 27, ,982 28,278 27,707 27, ,279 28,603 27,727 28, ,572 28,922 27,741 28, ,861 29,236 27,751 28, ,145 29,546 27,758 28, ,428 29,854 27,767 28, ,708 30,161 27,779 28, ,987 30,466 27,795 28, ,265 30,770 27,818 28, ,543 31,072 27,848 28, ,821 31,372 27,886 28, ,099 31,671 27,932 28, ,376 31,967 27,985 29, ,653 32,260 28,044 29, ,928 32,550 28,106 29, ,201 32,837 28,170 29, ,471 33,120 28,233 29, ,738 33,399 28,292 29, ,001 33,673 28,344 29, ,259 33,942 28,388 29, ,511 34,204 28,422 29, ,756 34,460 28,444 29,778 Edge Analytics Ltd 11

12 Kettering Population Forecasts Kettering - Population growth - Natural Change Emerging Approach A & B ,255 61,255 61,255 61, ,745 62,072 61,745 61, ,519 62,955 62,519 62, ,824 63,386 62,824 62, ,266 63,954 63,266 63, ,663 64,529 63,663 63, ,323 65,363 64,323 64, ,676 65,903 64,676 64, ,212 66,663 65,212 65, ,688 67,333 65,484 65, ,159 67,998 65,743 66, ,627 68,662 65,991 66, ,096 69,327 66,230 66, ,565 69,994 66,461 67, ,039 70,666 66,689 67, ,518 71,345 66,914 68, ,004 72,029 67,137 68, ,495 72,718 67,359 69, ,990 73,410 67,579 70, ,488 74,103 67,798 70, ,987 74,796 68,014 71, ,486 75,489 68,228 72, ,983 76,179 68,439 73, ,477 76,866 68,649 74, ,966 77,548 68,855 75, ,449 78,223 69,057 76, ,924 78,892 69,254 77, ,390 79,553 69,446 77, ,847 80,205 69,632 78, ,294 80,849 69,812 79, ,731 81,483 69,983 80,471 Edge Analytics Ltd 12

13 Rothwell and Desborough Population Forecasts Rothwell and Desborough - Population growth - Natural Change Emerging Approach A & B ,049 21,049 21,049 21, ,311 21,429 21,311 21, ,775 21,925 21,775 21, ,370 22,573 22,370 22, ,721 22,967 22,721 22, ,182 23,501 23,182 23, ,973 24,376 23,973 23, ,670 25,138 24,670 24, ,871 25,422 24,871 24, ,394 26,020 24,984 25, ,916 26,616 25,084 25, ,437 27,213 25,173 26, ,957 27,809 25,253 26, ,478 28,407 25,325 27, ,000 29,005 25,393 27, ,524 29,606 25,456 27, ,050 30,208 25,518 28, ,576 30,811 25,577 28, ,105 31,416 25,637 28, ,634 32,020 25,696 28, ,164 32,626 25,757 29, ,695 33,232 25,819 29, ,227 33,839 25,882 29, ,760 34,447 25,947 29, ,294 35,056 26,013 29, ,829 35,665 26,080 29, ,364 36,276 26,146 29, ,899 36,886 26,210 29, ,433 37,497 26,271 29, ,967 38,107 26,330 29, ,500 38,716 26,384 29,978 Edge Analytics Ltd 13

14 Wellingborough Population Forecasts Wellingborough - Population growth - Natural Change Emerging Approach A Emerging Approach B ,547 72,547 72,547 72,547 72, ,163 72,848 73,163 73,163 73, ,260 72,957 73,260 73,260 73, ,626 73,260 73,626 73,626 73, ,520 74,061 74,520 74,520 74, ,907 74,324 74,907 74,907 74, ,161 74,579 75,161 75,161 75, ,573 75,209 75,573 75,573 75, ,656 75,663 75,656 75,656 75, ,059 76,144 75,971 76,059 76, ,456 76,618 76,266 75,925 75, ,847 77,089 76,543 75,964 75, ,236 77,559 76,805 76,020 75, ,622 78,030 77,055 76,141 76, ,011 78,505 77,298 76,380 76, ,403 78,986 77,537 76,681 76, ,799 79,473 77,773 77,050 76, ,195 79,961 78,007 77,561 77, ,590 80,448 78,238 78,147 77, ,983 80,933 78,467 78,794 78, ,370 81,411 78,694 79,556 79, ,751 81,882 78,918 80,407 79, ,124 82,344 79,139 81,260 80, ,486 82,796 79,356 82,107 81, ,837 83,237 79,569 82,999 82, ,175 83,667 79,777 83,939 83, ,499 84,083 79,977 84,803 83, ,808 84,486 80,168 85,651 84, ,102 84,874 80,349 86,515 85, ,378 85,247 80,517 87,391 86, ,638 85,604 80,671 88,251 86,978 Edge Analytics Ltd 14

15 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 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,621 Edge Analytics Ltd 15

16 Corby - Household forecast Corby Household forecasts - Natural Change Emerging Approach A & B ,790 21,790 21,790 21, ,886 21,850 21,886 21, ,952 21,912 21,952 21, ,009 22,053 22,009 22, ,237 22,368 22,237 22, ,326 22,616 22,326 22, ,506 23,085 22,506 22, ,716 23,606 22,716 22, ,985 24,149 22,985 22, ,206 24,643 23,126 23, ,442 25,150 23,274 23, ,665 25,635 23,405 24, ,896 26,134 23,537 24, ,126 26,651 23,662 25, ,360 27,156 23,803 26, ,594 27,677 23,962 26, ,834 28,220 24,138 27, ,068 28,772 24,308 28, ,290 29,304 24,470 28, ,504 29,844 24,621 29, ,687 30,349 24,735 30, ,896 30,886 24,879 30, ,102 31,420 25,011 31, ,306 31,959 25,136 32, ,498 32,479 25,257 33, ,700 33,006 25,395 33, ,909 33,535 25,546 34, ,113 34,054 25,691 35, ,299 34,562 25,821 36, ,481 35,072 25,943 36, ,672 35,600 26,070 37,573 Four Towns - Household forecast Four Towns Household forecasts - Natural Change Emerging Approach A & B ,268 21,268 21,268 21, ,791 21,884 21,791 21, ,334 22,467 22,334 22, ,642 22,789 22,642 22, ,919 23,066 22,919 22, ,354 23,538 23,354 23, ,670 23,978 23,670 23, ,830 24,267 23,830 23, ,925 24,496 23,925 23, ,156 24,867 23,913 24, ,404 25,239 23,929 24, ,662 25,575 23,970 24, ,953 25,930 24,068 24, ,273 26,303 24,217 24, ,601 26,627 24,374 24, ,964 27,015 24,574 25, ,297 27,386 24,742 25, ,625 27,776 24,908 25, ,949 28,162 25,071 26, ,264 28,548 25,230 26, ,567 28,920 25,373 26, ,850 29,264 25,492 27, ,159 29,632 25,635 27, ,475 30,009 25,786 27, ,789 30,387 25,941 28, ,083 30,734 26,068 28, ,358 31,049 26,174 28, ,653 31,389 26,301 29, ,946 31,735 26,430 29, ,228 32,068 26,545 29, ,491 32,382 26,636 30,189 Edge Analytics Ltd 16

17 Rural North, Oundle and Thrapston Household forecasts Rural North, Oundle and Thrapston - Household forecast - Natural Change Emerging Approach A & B ,093 10,093 10,093 10, ,244 10,289 10,244 10, ,426 10,485 10,426 10, ,534 10,599 10,534 10, ,681 10,754 10,681 10, ,801 10,892 10,801 10, ,958 11,099 10,958 10, ,112 11,292 11,112 11, ,201 11,419 11,201 11, ,337 11,590 11,190 11, ,464 11,749 11,173 11, ,598 11,907 11,171 11, ,743 12,074 11,207 11, ,893 12,240 11,278 11, ,063 12,402 11,385 11, ,232 12,572 11,486 11, ,397 12,743 11,594 11, ,564 12,923 11,696 12, ,736 13,110 11,802 12, ,898 13,289 11,893 12, ,058 13,465 11,971 12, ,218 13,641 12,039 12, ,388 13,826 12,115 12, ,552 14,005 12,177 12, ,713 14,177 12,231 12, ,878 14,352 12,288 12, ,038 14,519 12,336 12, ,205 14,694 12,388 12, ,370 14,869 12,440 12, ,526 15,034 12,476 13, ,679 15,198 12,501 13,105 Kettering - Household forecast Kettering Household forecasts - Natural Change Emerging Approach A & B ,814 25,814 25,814 25, ,104 26,191 26,104 26, ,512 26,647 26,512 26, ,688 26,868 26,688 26, ,948 27,169 26,948 26, ,151 27,466 27,151 27, ,455 27,874 27,455 27, ,651 28,210 27,651 27, ,934 28,599 27,934 27, ,179 28,963 28,050 28, ,445 29,337 28,184 28, ,698 29,696 28,300 28, ,999 30,089 28,457 28, ,292 30,473 28,597 29, ,609 30,862 28,769 29, ,923 31,259 28,948 29, ,229 31,650 29,120 30, ,541 32,064 29,296 30, ,857 32,480 29,474 30, ,151 32,877 29,630 31, ,466 33,303 29,807 31, ,749 33,692 29,953 32, ,041 34,088 30,105 32, ,326 34,475 30,248 33, ,606 34,862 30,393 33, ,907 35,260 30,564 34, ,217 35,669 30,748 34, ,504 36,050 30,911 34, ,801 36,446 31,086 35, ,091 36,830 31,253 35, ,351 37,189 31,394 36,294 Edge Analytics Ltd 17

18 Rothwell and Desborough Household forecasts Rothwell and Desborough - Household forecast - Natural Change Emerging Approach A & B ,679 8,679 8,679 8, ,826 8,859 8,826 8, ,034 9,083 9,034 9, ,286 9,357 9,286 9, ,492 9,578 9,492 9, ,726 9,848 9,726 9, ,043 10,209 10,043 10, ,357 10,570 10,357 10, ,462 10,713 10,462 10, ,709 11,004 10,511 10, ,936 11,269 10,541 10, ,171 11,543 10,586 11, ,410 11,814 10,633 11, ,662 12,102 10,683 11, ,927 12,394 10,750 11, ,178 12,678 10,805 11, ,440 12,973 10,873 12, ,696 13,268 10,928 12, ,962 13,571 10,985 12, ,207 13,855 11,025 12, ,438 14,123 11,055 12, ,694 14,420 11,112 12, ,937 14,702 11,157 12, ,183 14,987 11,202 12, ,426 15,269 11,248 12, ,678 15,557 11,301 12, ,952 15,869 11,373 13, ,207 16,157 11,428 13, ,476 16,464 11,505 13, ,730 16,752 11,558 13, ,996 17,055 11,614 13,377 Wellingborough Household forecasts Wellingborough - Household forecast - Natural Change Emerging Approach A Emerging Approach B ,128 30,128 30,128 30,128 30, ,635 30,515 30,635 30,635 30, ,777 30,670 30,777 30,777 30, ,948 30,816 30,948 30,948 30, ,435 31,235 31,435 31,435 31, ,685 31,425 31,685 31,685 31, ,852 31,630 31,852 31,852 31, ,088 31,952 32,088 32,088 32, ,223 32,220 32,223 32,223 32, ,518 32,573 32,441 32,518 32, ,829 32,921 32,664 32,626 32, ,108 33,220 32,847 32,768 32, ,418 33,549 33,050 32,946 32, ,741 33,884 33,250 33,159 33, ,056 34,187 33,458 33,407 33, ,382 34,521 33,691 33,692 33, ,718 34,878 33,939 34,011 33, ,031 35,214 34,168 34,366 34, ,348 35,559 34,397 34,757 34, ,671 35,924 34,630 35,182 35, ,981 36,269 34,847 35,643 35, ,285 36,604 35,056 36,140 35, ,584 36,945 35,259 36,636 36, ,881 37,291 35,455 37,133 36, ,155 37,604 35,644 37,629 37, ,405 37,893 35,818 38,126 37, ,679 38,201 36,023 38,622 38, ,951 38,503 36,236 39,119 38, ,210 38,790 36,443 39,615 39, ,457 39,061 36,633 40,112 39, ,704 39,338 36,829 40,608 40,083 Edge Analytics Ltd 18

19 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 ) 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 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,878 Edge Analytics Ltd 19

20 Corby - Labour force forecast Corby Labour Force forecasts - Natural Change Emerging Approach A & B ,731 32,486 29,552 30, ,773 32,912 29,515 30, ,847 33,379 29,510 31, ,949 33,878 29,535 32, ,991 34,322 29,499 32, ,045 34,776 29,473 33, ,111 35,246 29,464 34, ,138 35,672 29,412 34, ,137 36,066 29,330 35, ,186 36,520 29,301 36, ,237 36,969 29,272 36, ,317 37,434 29,265 37, ,411 37,917 29,266 38, ,563 38,461 29,319 39, ,723 39,004 29,367 40, ,787 39,481 29,325 40, ,888 40,016 29,313 41, ,975 40,527 29,280 42, ,078 41,049 29,263 43, ,138 41,538 29,199 43, ,198 42,031 29,134 44,629 Four Towns Labour Force forecasts Four Towns - Labour force forecast - Natural Change Emerging Approach A & B ,981 31,970 30,632 30, ,049 32,098 30,528 30, ,113 32,240 30,420 30, ,199 32,407 30,335 30, ,322 32,602 30,279 30, ,457 32,817 30,236 30, ,534 32,974 30,137 30, ,657 33,159 30,087 30, ,779 33,336 30,037 30, ,972 33,590 30,059 30, ,150 33,827 30,061 30, ,270 34,002 30,009 31, ,437 34,221 29,992 31, ,649 34,474 30,024 31, ,852 34,705 30,042 31, ,999 34,896 29,995 32, ,156 35,100 29,958 32, ,268 35,266 29,865 32, ,351 35,417 29,753 32, ,345 35,496 29,553 32, ,301 35,507 29,322 32,961 Edge Analytics Ltd 20

21 Rural North, Oundle and Thrapston Labour Force forecasts Rural North, Oundle and Thrapston - Labour force forecast - Natural Change Emerging Approach A & B ,566 14,809 14,424 14, ,612 14,857 14,392 14, ,656 14,918 14,353 14, ,725 15,004 14,333 14, ,800 15,094 14,310 14, ,864 15,176 14,271 14, ,959 15,290 14,254 14, ,017 15,354 14,199 14, ,068 15,407 14,128 14, ,153 15,498 14,078 14, ,234 15,584 14,024 14, ,316 15,670 13,966 14, ,387 15,745 13,887 13, ,488 15,843 13,829 13, ,557 15,904 13,740 13, ,619 15,963 13,633 13, ,676 16,017 13,517 13, ,702 16,040 13,373 13, ,717 16,061 13,216 13, ,689 16,052 13,042 13, ,666 16,026 12,883 13,445 Kettering Labour Force forecasts Kettering - Labour force forecast - Natural Change Emerging Approach A & B ,289 36,456 34,929 35, ,310 36,605 34,785 35, ,341 36,764 34,659 35, ,403 36,950 34,567 35, ,489 37,160 34,502 35, ,626 37,425 34,488 35, ,778 37,701 34,488 35, ,946 37,985 34,502 35, ,074 38,232 34,474 36, ,252 38,520 34,498 36, ,417 38,784 34,514 36, ,575 39,038 34,519 37, ,710 39,279 34,507 37, ,878 39,551 34,530 38, ,027 39,797 34,538 38, ,149 40,035 34,518 38, ,239 40,234 34,460 39, ,335 40,437 34,406 39, ,399 40,593 34,310 39, ,411 40,714 34,168 39, ,436 40,831 34,037 40,167 Edge Analytics Ltd 21

22 Rothwell and Desborough Labour Force forecasts Rothwell and Desborough - Labour force forecast - Natural Change Emerging Approach A & B ,920 14,362 13,387 13, ,076 14,565 13,280 14, ,250 14,788 13,190 14, ,425 15,011 13,101 14, ,575 15,206 12,993 14, ,740 15,419 12,904 14, ,916 15,641 12,834 14, ,114 15,881 12,788 14, ,312 16,124 12,748 14, ,552 16,405 12,745 14, ,762 16,650 12,710 14, ,992 16,915 12,692 14, ,246 17,210 12,687 14, ,475 17,477 12,657 14, ,712 17,750 12,629 14, ,936 18,016 12,592 14, ,196 18,318 12,580 14, ,430 18,591 12,541 14, ,625 18,818 12,472 14, ,807 19,042 12,392 14, ,996 19,264 12,312 14,340 Wellingborough Labour Force forecasts Wellingborough - Labour force forecast - Natural Change Emerging Approach A Emerging Approach B ,900 40,733 40,577 40,558 40, ,828 40,681 40,363 40,267 40, ,805 40,666 40,204 40,040 40, ,854 40,738 40,122 39,931 39, ,904 40,814 40,046 39,900 39, ,962 40,897 39,981 39,918 39, ,983 40,954 39,883 39,942 39, ,014 41,023 39,798 40,066 39, ,024 41,059 39,697 40,216 40, ,077 41,132 39,645 40,446 40, ,089 41,163 39,551 40,709 40, ,178 41,275 39,537 41,103 40, ,251 41,367 39,507 41,481 41, ,342 41,480 39,497 41,872 41, ,406 41,571 39,458 42,264 41, ,417 41,616 39,369 42,632 42, ,442 41,674 39,284 42,969 42, ,460 41,734 39,195 43,290 42, ,431 41,751 39,058 43,575 42, ,364 41,737 38,882 43,834 43, ,272 41,689 38,679 44,063 43,336 Edge Analytics Ltd 22

23 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 , 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 mid-year estimates released by ONS in 2010, and the 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, 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) Corby 2 Four T 3 RNOT 4 Ktring 5 R-Des 6 Wbrgh 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 Edge Analytics Ltd 23

24 Rate per 1,000 population Total fertility Rate (TFR) 2008-based Deaths and mortality The forecasting process uses the following death and mortality information: Mid-year counts of deaths Deaths by age and sex from 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) Newborn Age 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

25 Standardised Mortality Ratio (SMR) 2008-based 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 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

26 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

27 Dwelling growth Corby Four Towns RNOT Kettering R & D Wellingborough A Wellingborough B 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

28 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/ / / / / / / / / / / / / / / / / / / / Total ,356 6,324 3,372 6,123 5,221 6,037 Corby Four Towns RNOT Kettering R-Des Wellingborough 2011/ / / / / / / / / / / / / / / / / / / / Total ,758 7,423 3,620 8,140 5,972 6,594 Edge Analytics Ltd 28

29 Natural Change Corby Four Towns RNOT Kettering R-Des Wellingborough 2011/ / / / / / / / / / / / / / / / / / / / Total ,881 2,814 1,393 3,328 1,107 4, 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 with the average applied in the model. Northamptonshire Males Females Economic Activity Rate (%) Average ret Ret ret Ret Source: NOMIS Edge Analytics Ltd 29

30 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. 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

31 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