Insights from the Evaluation of Past Local Area Population Forecasts

Local area population forecasts have a wide variety of uses in the public and private sectors. But not enough is known about the errors of such forecasts, particularly over the longer term (20 years or more). Understanding past errors is valuable for both forecast producers and users. This paper (i) evaluates the forecast accuracy of past local area population forecasts published by Australian State and Territory Governments over the last 30 years and (ii) illustrates the ways in which past error distributions can be employed to quantify the uncertainty of current forecasts. Population forecasts from the past 30 years were sourced from State and Territory Governments. Estimated resident populations to which the projections were compared were created for the geographical regions of the past projections. The key features of past forecast error patterns are described. Forecast errors mostly confirm earlier findings with regard to the relationship between error and length of projection horizon and population size. The paper then introduces the concept of a forecast ‘shelf life’, which indicates how far into the future a forecast is likely to remain reliable. It also illustrates how past error distributions can be used to create empirical prediction intervals for current forecasts. These two complementary measures provide a simple way of communicating the likely magnitude of error that can be expected with current local area population forecasts.     

Stochastic Forecasting of Labor Supply and Population: An Integrated Model

This paper presents a stochastic model to forecast the German population and labor supply until 2060. Within a cohort-component approach, our population forecast applies principal components analysis to birth, mortality, emigration, and immigration rates, which allows for the reduction of dimensionality and accounts for correlation of the rates. Labor force participation rates are estimated by means of an econometric time series approach. All time series are forecast by stochastic simulation using the bootstrap method. As our model also distinguishes between German and foreign nationals, different developments in fertility, migration, and labor participation could be predicted. The results show that even rising birth rates and high levels of immigration cannot break the basic demographic trend in the long run. An important finding from an endogenous modeling of emigration rates is that high net migration in the long run will be difficult to achieve. Our stochastic perspective suggests therefore a high probability of substantially decreasing the labor supply in Germany.     

Long-Term Earnings Differentials Between African American and White Men by Educational Level

This paper investigates long-term earnings differentials between African American and white men using data that match respondents in the Survey of Income and Program Participation to 30 years of their longitudinal earnings as recorded by the Social Security Administration. Given changing labor market conditions over three decades, we focus on how racial differentials vary by educational level because the latter has important and persistent effects on labor market outcomes over the course of an entire work career. The results show that the long-term earnings of African American men are more disadvantaged at lower levels of educational attainment. Controlling for demographic characteristics, work disability, and various indicators of educational achievement does not explain the lower long-term earnings of less-educated black men in comparison to less-educated white men. The interaction arises because black men without a high school degree have a larger number of years of zero earnings during their work careers. Other results show that this racial interaction by educational level is not apparent in cross-sectional data which do not provide information on the accumulation of zero earnings over the course of 30 years. We interpret these findings as indicating that compared to either less-educated white men or highly educated black men, the long-term earnings of less-educated African American men are likely to be more negatively affected by the consequences of residential and economic segregation, unemployment, being out of the labor force, activities in the informal economy, incarceration, and poorer health.     

Conducive Characteristics or Anti-Racist Context? Decomposing the Reasons for Veterans’ High Likelihood of Interracial Marriage

Over the twentieth and twenty-first centuries, veterans have been more likely to enter into race/ethnic intermarriages than non-veterans. Theories of race/ethnic intermarriage variously point to how minority race/ethnicity, race/ethnically diverse social settings, progressive racial attitudes, and high socioeconomic status increase individuals’ likelihood of intermarrying. Veterans’ unique racial and socioeconomic characteristics may contribute to their greater likelihood of intermarrying relative to non-veterans: larger percentages of veterans than non-veterans are members of racial and ethnic minority groups, while military service increases individual service members’ long-term economic and educational prospects. At the same time, veterans share in common their exposure to the unique military environment, which may increase their likelihood of intermarriage by diversifying their social circles, and subjecting their attitudes and behavior to group norms that are more explicitly egalitarian than those of society at large. The present study considers these two possible explanations for veterans’ greater likelihood of intermarriage. We use data on seven cohorts of men over six decades in the Current Population Survey, representing a total of 1,456,742 observations, to decompose the difference in likelihood of racial intermarriage between veterans and non-veterans among married men aged 18–65. We find that across cohorts and decades, veterans’ greater likelihood of intermarrying is not fully explained by their race/ethnic and socioeconomic composition. We argue that veterans’ greater likelihood of intermarrying may therefore be driven by their exposure to the military environment.     

Estimating Recent Local Impacts of Sea-Level Rise on Current Real-Estate Losses: A Housing Market Case Study in Miami-Dade,Florida

Sea-Level Rise (SLR) Projections from the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Army Corp of Engineers (USACE) indicate increasing, and imminent, risk to coastal communities from tidal flooding and hurricane storm surge. Building on recent research related to the potential demographic impacts of such changes (Hauer et al. 2016, in Nat Clim Chang 3:802–806, 2017; Neumann et al. 2015; Curtis and Schneider in Popul Environ 33:28–54, 2011), localized flooding projections in the Miami Beach area (Wdowinski et al. in Ocean Coast Manag 126:1–8, 2016) and projected economic losses associated with this rise in projected SLR (Fu et al. Ocean Coast Manag 133:11–17, 2016); this research investigates the accrued current cost, in terms of real-estate dollars lost, due to recurrent tidal flooding and projected increases of flooding in Miami-Dade County. Most directly related to this line of research, Keenan et al. (2018) have recently produced results indicating that Climate Gentrification is taking place in Miami, FL with higher elevations in flood prone areas appreciating at a higher rate. In that vein of thinking, we seek to answer a question posed by such research: What is the actual accrued loss to sea-level rise over the recent past? To answer this question, we replicate well-documented estimation methods by combining publicly available sea-level rise projections, tide gauge trends, and property lot elevation data to identify areas regularly at risk of flooding. Combining recent patterns of flooding inundation with future forecasts, we find that properties projected to be inundated with tidal flooding in 2032 have lost $3.08 each year on each square foot of living area, and properties near roads that will be inundated with tidal flooding in 2032 have lost $3.71 each year on each square foot of living area. These effects total over $465 million in lost real-estate market value between 2005 and 2016 in the Miami-Dade area.     

SNAP Benefits and Pregnancy-Related Emergency Room Visits

Pregnant women are likely to be sensitive to daily fluctuations in nutritional intake. To see if income constraints at the end of the month limit food consumption and trigger health problems, we examine how the date that benefits are issued for the Supplemental Nutrition Assistance Program (SNAP) changes the probability that a woman will go to the Emergency Room (ER) for pregnancy-related conditions using administrative data from SNAP and Medicaid from Missouri for 2010–2013. SNAP benefits in Missouri are distributed from the 1st through the 22nd day of the month based on the birth month and the first letter of the last name of the head of the household, making timing of SNAP issuance exogenous. We estimate probit models of the calendar month and SNAP benefit month on the probability of a pregnancy-related ER visit for women age 17–45, or the sample at risk of being pregnant. We also examine the relationship between SNAP benefit levels and ER visits. We found that women who received SNAP benefits in the second or third week of the calendar month were less likely to receive pregnancy-related care through the ER in the week following benefit receipt. Results suggest that SNAP benefits might be related to patterns of pregnancy-related medical care accessed through the ER. Since SNAP issuance date is within state control in the United States, states may want to consider the health effects of their choice.     

Subsequent Migration of Immigrants Within Australia, 1981–2016

Australia is a major immigration country and immigrants currently represent around 28% of the total population. The aim of this research is to understand the long-term consequences of this immigration and, particularly, how migrants respond to opportunities within the country after arriving through the process of subsequent (internal) migration. The focus is on major immigrant groups in Australia, including persons born in the United Kingdom, New Zealand, China and India, and how their patterns differ from persons born in Australia. To conduct this analysis, we have gathered data for a 35-year period based on quinquennial census data. We also obtained birthplace-specific mortality data for constructing multiregional life tables for the immigrant populations. Subsequent migration is important for understanding population redistribution, and the relative attractiveness of destinations within host countries. Our results highlight the importance of subsequent migration and the diversity of migration behaviours amongst different immigrant groups in the context of overall declines in internal migration since 1981.     

Business Cycles,Medicaid Generosity,and Birth Outcomes

Birth outcomes influence many aspects of later life health and wellbeing, making healthcare access during pregnancy a policy priority. Low-income mothers often depend on Medicaid, for which eligibility is determined by their income relative to state eligibility thresholds. The prevalence of adverse birth outcomes is known to exhibit cyclical variation, due in part to changes in the composition of women giving birth in response to changing economic conditions. However, cyclical variation in adverse birth outcomes also varies with respect to Medicaid eligibility thresholds. Our analysis uses birth-records data for 2000 through 2013, aggregated into 173,936 county-by-quarter observations and linked to county-level unemployment rates and state-level parental Medicaid thresholds. Using fixed-effects negative binomial models, we examine the role of Medicaid generosity in influencing birth outcomes across business cycles. We test for interactions between Medicaid and unemployment, hypothesizing that the negative effects of recessions are worse where Medicaid thresholds are more restrictive. We find that higher Medicaid generosity dampens the negative effects of recessions on birth outcomes. The extent to which Medicaid interacts with unemployment also varies according to the age and race composition of mothers; in particular, Black mothers are both most affected by unemployment and most responsive to Medicaid generosity. Given current concerns about racial gaps in both infant and maternal mortality, our findings suggest that Medicaid may be an important feature of a strategy to close gaps in the prevalence of adverse birth outcomes across racial groups, especially during bust years.     

The Evolving and Complementary Impacts of Transportation Infrastructures on Population and Employment Change in the United States, 1970–2010

Transportation infrastructures play an essential role in influencing population and employment change. While railroads, highways, and airports were constructed in different time periods, now they complement each other in terms of providing accessibility. This study uses county-level data to examine the impacts of the three forms of transportation infrastructure on population and employment change in the continental United States from 1970 to 2010. The findings suggest that transportation infrastructures play evolving but complementary roles in affecting population and employment change during the study period: railroads act as a distributive factor, highways take a facilitator role, and airports behave like growth poles. Diversification of the roles indicates that transportation infrastructures have evolved from a pure growth factor to an essential multifaceted development element of human society.