1 / 30

ASSESS, York 2013 Using SPSS to estimate demographic rates by ethnic group Paul Norman

ASSESS, York 2013 Using SPSS to estimate demographic rates by ethnic group Paul Norman Centre for Spatial Analysis & Policy School of Geography University of Leeds. ESRC Research Awards RES-189-25-0162 & RES-165-25-0032

paxton
Download Presentation

ASSESS, York 2013 Using SPSS to estimate demographic rates by ethnic group Paul Norman

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ASSESS, York 2013 Using SPSS to estimate demographic rates by ethnic group Paul Norman Centre for Spatial Analysis & Policy School of Geography University of Leeds ESRC Research Awards RES-189-25-0162 & RES-165-25-0032 What happens when international migrants settle? Ethnic group population trends and projections for UK local areas

  2. Context • Population projections • Why by ethnic group • How operationalised • Estimating fertility rates by ethnic group • Data sources • Estimation steps • Logistic regression (SPSS) • Constraints & scaling (Excel) • Nonlinear regression (SPSS) • Estimating migration and mortality rates

  3. Population projections? Past Now ‘Latest available data’ Future Based on available evidence of population counts or indicators of change Forecasts Projections Estimates Census 2001 Census 2011 Some predictions are made about what may happen to demographic trends

  4. Population projections? • Age-sex structure & demographic rates leads to different age-sex structure 2001 Population • Age-Specific Fertility Rates … a.) TFR = 1.69 b.) TFR = 1.44 a.) 9,788 babies = 5,013 boys & 4,774 girls b.) 7,927 babies = 4,060 boys & 3,867 girls … & age-sex specific mortality & migration rates

  5. Population projections by ethnic group: Why? • Applied reasons • Age-sex counts by ethnic group needed … for equal opportunities, education support, denominators e.g. health • Output quality reasons • If sub-groups ‘behave’ differently, the quality of the whole will be improved • Fertility, Mortality, Migration ethnic group differences? • Cultural choices, lifestyle, aspiration, socioeconomic position, etc

  6. Population projections by ethnic group • Specification: • Time-frame: annually 2001-2051 • Geography: Local authorities in England plus countries of Wales, Scotland, Northern Ireland • Ethnic groups: 16 groups re 2001 Census • Inputs: • Age-sex populations for 2001 • Demographic rates for 2001 & future ‘assumptions’ • Fertility • Mortality • Subnational & International Migration • All by 16 ethnic groups

  7. Vital Statistics • ASFRs for all women, LA Estimate ASFRs by ethnic group • Populations • Ethnic group, LA • LFS Sample • ASFRs by ethnic group, national Estimating fertility rates by ethnic group Data on fertility by ethnic group not directly collected • 1. Labour Force Survey (5YA) • ASFRs by ethnic group, national • Microdata: estimate probability of child by ethnic group • Logistic regression (SPSS) • 2. Constrain / scale to VS (5YA) • Adjust probabilities to sum to births to all women by Local Authority (Excel) • 3. Estimate single year of age rates from the 5 year information • Nonlinear regression (SPSS)

  8. 1. Evidence of age-specific fertility by ethnic group • Labour Force Survey • Collected annually 1980s to date • Respondent by age, sex, ethnic group • Presence of dependent child (0-4) • Derive time-trends in fertility • Pros? All of the above • Cons? Some of the above

  9. 1. Labour Force Survey • Data view • 2001 sub-sample • Syntax: • Filter for year & subgroup • Logistic regression

  10. 1. Labour Force Survey • Logistic regression outputs

  11. 2. Constrain / scale to VS Estimating fertility rates: national

  12. 2. Local variation in ethnic fertility For each LA … Scale local ASFR(aw) by National ASFR (e) Scale ASFR(e) by local TFR (e) Calculate births by ethnic groups Fit births to VS Bradford Iterate to fit Recalculate ASFRs

  13. 3. Estimating single year of age information • Projection model • Time-frame: annually 2001-2051 • Needs single year of age information • Disaggregate 5 year ASFRs to be SYA • By 16 ethnic groups by 350+ LAs • Nonlinear model • Use nonlinear regression in SPSS • Predict rates by SYA based on 5YA information

  14. 3. Nonlinear regression (NLR) • NLR • Not easy to get into doing • Not covered in ‘how to’ textbooks • Published papers define curves using algebra • Scary definitions • Difficult to work out how to implement • What’s the point of NLR? • Think of it as estimation (prediction) … • … not explanation (prediction) as in OLS, etc.

  15. 3. Nonlinear regression (NLR) Ragged data Grouped data • Generic terms • Smoothing • Graduation • Curve fitting / estimation • Terms in widespread use • Loose definitions • Different techniques

  16. 3. Nonlinear regression (NLR): How? • Exploratory • Scatterplot gives idea of shape of curve in data • Pick function likely to be appropriate (h * exp( – (x – p)**2 / r)) Where: x = the increments (e.g. age) h = height of the curve p = position on the x axis r = rate of ascent & descent exp = exponential function (h * exp( – rd * (x – p) – exp( – ra * (x – p)))) Where: ra = rate of ascent rd = rate of descent

  17. 3. Nonlinear regression (NLR): How? (h * exp(r * x)) (h * exp( – r * x)) a / (1 + exp(b + c * x)) a * exp(– exp(b – c * x))

  18. 3. Disaggregating grouped data using NLR a. Take grouped data & / 5 (or similar)

  19. 3. Disaggregating grouped data using NLR • b.) Having eye-balled the type of curve • c.) Pick appropriate function • d.) Make intelligent guess on starting parameters • Not always clear what to use! • NLR routine estimates parameters during the modelling

  20. 3. Disaggregating grouped data using NLR • e.) Write (edit) SPSS syntax (dialogue box iffy) • MODEL PROGRAM h=50 p=25 r=0.5 . • COMPUTE curve1_pr = (h*exp(-(unit-p)**2/r)) . • NLR curve1 • /PRED curve1_pr • /SAVE PRED • /CRITERIA ITER 1000 . • VARIABLE LABELS curve1_pr 'Predicted Data' . • * . • *Estimated curve . • TSPLOT VARIABLES= curve1 curve1_pr • /ID= unit • /NOLOG. • f.) Run the syntax

  21. 3. Disaggregating grouped data using NLR g.) Look at SPSS Output & Data Editor

  22. 3. Disaggregating grouped data using NLR • h.) Assessing model fit (& comparing models) • Statistical measures: R2 & others • Interpretive: Parameters might mean something • Practical: Use the outputs (apply rates to population) • Visual: How pretty are the smooth curves?!

  23. Modelling demographic rates Fertility curves: MODEL PROGRAM a=1 b=4 c=28. COMPUTE White_Pr = (a*b/c)*(c/age)**(3/2)*exp(-b*b*(c/age+age/c-2)). NLR wht /PRED White_Pr /SAVE PRED /CRITERIA ITER 10000 . VARIABLE LABELS White_Pr 'White Pred_Val Hadwiger' .

  24. Modelling demographic rates Mortality curves: MODEL PROGRAM A=1 B=1 C=1 D=1 E=10 F=20 G=1 H=1 K=2 . COMPUTE dth_pr = A**(age+B)**C + D*exp(-E*(ln(age)-ln(F))**2) + G*H**age / 1+K*G*H**age . NLR pr_death /PRED dth_pr /SAVE PRED /CRITERIA ITER 1000 . VARIABLE LABELS dth_pr 'Predicted Data' .

  25. Modelling demographic rates Migration curves: * 4 component (with elderly & retirement) with constant. * . MODEL PROGRAM h1=1 r1=0.1 h2=1 ra1=0.1 rd1=0.1 p1=25 h3=1 ra2=0.1 rd2=0.1 p2=55 h4=1 r2=0.1 . COMPUTE c1_in4pr = (h1*exp(-r1*age)) + (h2*exp(-rd1*(age-p1)-exp(-ra1*(age-p1)))) + (h3*exp(-rd2*(age-p2)-exp(-ra2*(age-p2)))) + (h4*exp(r2*age)) + 0.005 . NLR c1_in /PRED c1_in4pr /SAVE PRED /CRITERIA ITER 1000 .

  26. Nonlinear regression • Approach described above appropriate … • Disaggregate grouped information • Smoothing ragged data • … as an estimate & to understand data better • Bronchiolitis epidemic: Onset, peak & decay • Symmetrical cf asymmetrical? Original Predicted

  27. Nonlinear regression • Can I use other software than SPSS? • Yes: Stata, R, Minitab • Can I do this using different techniques? • Yes: functions in linear regression • Quadratic, Cubic, Quartic • Relational models • Kernel density, splines

  28. Population projections by ethnic group • Estimating demographic rates by ethnic group • Fertility using logistic regression, constraints & scaling & nonlinear regression • Resources • Material in this presentation drawn from: • Norman P, Marshall A, Thompson C, Williamson L & Rees P. (2012) Estimating detailed distributions from grouped sociodemographic data: ‘get me started in’ curve fitting using nonlinear regression. Journal of Population Research 29(2): 173-198 DOI: 10.1007/s12546-012-9082-9 • Norman P, Rees P & Wohland P (2013) The use of a new indirect method to estimate ethnic-group fertility rates for subnational projections for England. Population Studies: A Journal of Demography DOI: 10.1080/00324728.2013.810300 • SPSS files to try nonlinear regression • Curve-examples-Table1.sav • Curve-fitting-Table1.sps

  29. Projections by ethnic group, 2001-2051 Selected publications Demographic components Boden P & Rees P (2010) International migration: the estimation of immigration to local areas in England using administrative sources, Journal of the Royal Statistical Society, Series A (Statistics in Society) Norman P, Gregory I, Dorling D & Baker A (2008) Geographical trends in infant mortality: England and Wales, 1970–2006. Health Statistics Quarterly 40: 18-29 Norman P, Rees P & Wohland P (2013) The use of a new indirect method to estimate ethnic-group fertility rates for subnational projections for England. Population Studies: A Journal of Demography DOI: 10.1080/00324728.2013.810300 Norman P, Rees P, Wohland P & Boden P (2010) Ethnic group populations: the components for projection, demographic rates and trends. Chapter 14 in Stillwell, J. and van Ham, M. (eds.) Ethnicity and Integration. Series: Understanding Population Trends and Processes. Springer: Dordrecht: 289-315 Rees P, Wohland P & Norman P (2009) The estimation of mortality for ethnic groups at local scale within the United Kingdom. Social Science & Medicine 69: 1592–1607 Stillwell J, Hussain S & Norman P (2008) The internal migration propensities and net migration patterns of ethnic groups in Britain. Migration Letters 5(2): 135-150 Tromans N, Natamba E, Jefferies J & Norman P (2008) Have national trends in fertility between 1986 and 2006 occurred evenly across England and Wales? Population Trends 133: 7-19 Wohland P & Rees P (2009) Life Expectancy Variation across England’s Local Areas by Ethnic Group in 2001, Journal of Maps, v2010, 354-359. 10.4113/jom.2010.1110 Project outputs http://ethpop.org/

  30. Projections by ethnic group, 2001-2051 Selected publications Methods Marshall A, Norman P & Plewis I (2013) Developing a relational model of disability. European Journal Population (accepted) Norman P, Marshall A, Thompson C, Williamson L & Rees P. (2011) Estimating detailed distributions from grouped sociodemographic data: ‘get me started in’ curve fitting using nonlinear regression. Journal of Population Research 29(2): 173-198 DOI: 10.1007/s12546-012-9082-9 Williamson L & Norman P (2011) Developing strategies for deriving small population fertility rates. Journal of Population Research 28(2): 149-183, doi:10.1007/s12546-011-9059-0 Wohland P, Rees P, Norman P, Boden P & Jasinska M (2010) Ethnic Population Projections for the UK and Local Areas, 2001-2051. Working Paper 10/02, School of Geography, University of Leeds, Leeds Projections Rees P, Wohland P & Norman P (2012) The demographic drivers of future ethnic group populations for UK local areas 2001-2051. Geographical Journal Rees P, Wohland P, Norman P & Boden P (2011) A local analysis of ethnic group population trends and projections for the UK. Journal of Population Research 28(2): 129-148 doi: 10.1007/s12546-011-9047-4 Rees P, Wohland P, Norman P & Boden P (2012) Ethnic population projections for the UK, 2001-2051. Journal of Population Research 29: 45-89 DOI 10.1007/s12546-011-9076-z Project outputs http://ethpop.org/

More Related