Synthetic Cohort Approach Research Articles

Intragenerational occupational mobility of South Korea, 1998–2017: Implications of the gendered life course approach for mobility and inequality studies

This study examined intragenerational mobility in South Korea during the era of increasing inequality by applying a micro-class approach. We improved the methods of studying intragenerational mobility by accounting for non-employment and analyzing gendered age patterns of intragenerational mobility based on a synthetic cohort approach. Our analyses demonstrated the following. First, age patterns of intragenerational mobility greatly differed by gender: Men’s mobility patterns stabilized as they aged, but there was no such stabilization among women. Notably, movements in and out of labor markets were more frequent among women than men. The persistence of patriarchal culture during rapid economic development was responsible for this pattern. Second, intragenerational mobility did not increase in South Korea. This finding is different from that of the United States, where increasing intragenerational mobility partly countervailed the trends of rising inequality for stable intergenerational mobility. This difference warrants reconsidering the role of intragenerational mobility as a link between inequality and social mobility. We discuss the implications of these findings on the relationship between inequality and mobility and gendered life trajectories in South Korea.

The evolution of socio‐economic disparities in literacy skills from age 15 to age 27 in 20 countries

This study contributes to the literature by examining the evolution of socio‐economic disparities in literacy skills between age 15 and 27. It uses combined cross‐sectional data from the Programme for International Student Assessment and the Programme for the International Assessment of Adult Competencies in 20 countries and adopts a synthetic cohort approach. In the article we examine if there are differences in the evolution of socio‐economic disparities in literacy between the teenage years and young adulthood among high‐achieving students (90th percentile) and among low‐achieving students (10th percentile) and compare differences across education systems. We used parental education as an indicator of socio‐economic status. Findings indicate that on average, disparities in literacy skills observed at age 15 widen by 15% of a standard deviation by age 27. Such increase is determined by a more pronounced growth in achievement among individuals with tertiary educated parents than among individuals whose parents did not complete tertiary education. The increase in socio‐economic gaps between age 15 and 27 is more pronounced among low‐achieving students. The group that improves the most between age 15 and 27 is low‐achieving individuals with tertiary educated parents. We find that socio‐economic differences in educational attainment, NEET status and use of skills at home and in the workplace explain a large part of socio‐economic disparities in literacy achievement among young adults. Although countries with above‐average disparities at age 15 tend to also display above‐average disparities at age 27, we identify differences across countries.

Development and Validation of a Large Synthetic Cohort for the Study of Cardiovascular Health Across the Life Span.

We developed and validated a synthetic cohort approach to examine numbers of cardiovascular risk factors (CRFs) and adverse clinical events, including incident cardiovascular disease and all-cause mortality, across the life span from ages 20 years to 90 years. The current analysis included 40,875 participants from 7 large, population-based longitudinal epidemiologic studies (1948-2016). On the basis of a joint multilevel imputation model, we multiply imputed each participant's life-span numbers of CRFs and events using available records. To validate the imputed values, we partially removed the observed data and then compared the imputed and observed values. The complete life-span synthetic data set reflected the original observed data trends well. In our validation sample, the distributions of imputed CRFs and events were close to the observed distributions but with less variability. Bland-Altman plots indicated that there was a slightly negative trend in general, and the agreement bias was relatively small for the continuous CRFs. The hypothetical linear regression model suggested that the relationships between the CRFs and events were preserved in the imputed data set. This approach generated valid estimates of CRFs and events across the life span for African-American and White participants. The synthetic cohort may be sufficiently accurate to be useful in assessing the origins and timing of accumulating cardiovascular risk that can inform efforts to avoid cardiovascular disease development.

Abstract P196: Cardiovascular Health Across the Lifespan: The Development and Validation of a Synthetic Cardiovascular Cohort

Introduction: The burden of cardiovascular (CV) risk factors accumulates over the lifespan: however, little information on CV risk across the full lifespan is available. Synthetic cohorts offer the opportunity to understand CV health across the lifespan. In this study we developed and validated a synthetic cohort approach to examine CV risk factors from age 18-90 years of age. Methods: This study included African American and Caucasian participants from 7 cohorts in the Lifetime Risk Pooling Project. Individuals’ demographics (age, birth year, sex, race, SES), CV risk factors (smoking, total cholesterol, SBP, DBP, glucose, diabetes, lipid-lowering and antihypertensive meds) and outcomes (incident CVD and death) at each exam were included. To generate a complete set of values from age 18 to 90 for each participant, we multiply imputed the participant’s CV risk profile and outcome using the available exam records based on a joint multi-level imputation model. To validate our imputed values, we removed the observed CARDIA data with exam ages 18-30, MESA data with exam ages 50-59 and CHS data with exam ages 80-90. We then imputed the CV risk profile of these deleted values and compared imputed and observed values. Results: We included 41,387 participants (55% female, 30% African American, mean age 51 at baseline, avg follow-up time 20 yrs). In our validation sample, imputed CV risk factor levels were consistent with observed values at both younger and older ages (table) for BMI, SBP, DBP, glucose and total cholesterol. The prevalence of antihypertensive meds was 14.6% in the observed and 14.9% in the imputed data. Similar findings were shown for the prevalence of diabetes, current smoking, CVD events and death. Imputed prevalence of lipid-lowering meds was lower than observed rates (5% vs 12%). Conclusions: This synthetic cohort approach provides valid and unbiased estimates of CV risk factors across the lifespan. Future studies using this synthetic cohort can provide novel insights into the origins and accumulation of CVD.

Education, labour, and the demographic consequences of birth postponement in Europe

This paper questions the demographic consequences of birth postponement in Europe. Starting from the fact that there is no obvious link between the timing of first births and fertility levels in Europe, we deliver some indication that under certain circumstances, birth postponement involves the potential of facilitating rather than impedes starting a family. We apply a synthetic cohort approach and distinguish between different socio-economic determinants of the timing of first births by using the European Union Statistics on Income and Living Conditions (EU-SILC). Data is compiled specifically to reduce endogeneity and to eliminate structure effects. We find that the probability of becoming a mother is higher for those women who postpone first childbirth due to education and career investment in comparison to those who postpone due to unrealized labour market integration. Educated and economically active women certainly postpone first childbirth in comparison to women who are less educated and who are not working, but they end up with a higher probability of starting a family in comparison to women who are less educated and not working. The article contributes to the academic discussion of the circumstances that may lead birth postponement to result in higher fertility for younger cohorts in European countries.

Impact of oil booms and busts on human capital investment in the USA

This paper uses Census IPUMS data from 1970 to 2000 and ACS data from 2010 to estimate the impact of oil booms and busts on wages and human capital formation in the USA. The paper finds that the oil boom between 1970 and 1980 was associated with a slower growth in the relative demand for skills in the oil and gas sector and regions where the sector had a large presence. The oil boom led to a sharp rise in real wages and a modest decline in college wage premium in oil-rich regions in the USA. Using a synthetic cohort approach, the paper finds that relative to cohorts who went to high school in the pre-oil boom period, the cohort reaching high school age during the oil boom was about 1–2% points less likely to have a college degree by 2000 and 2010.

Transition to adulthood in China in 1982−2005: A structural view

1. IntroductionThe transition to adulthood includes certain trajectories, such as leaving school, entering the labor force, getting married, and having children. These transitions have been increasingly postponed, shuffled, and individualized in the United States and Western Europe (for reviews, see Buchmann and Kriesi 2011; Settersten and Bay 2010; Shanahan 2000). Less is known about changes in the transition to adulthood in nonWestern countries, especially whether they follow a similar pattern of change. Some research suggests that aspects of these changes mimic those of the West (Lesthaeghe 2010; Lloyd 2005). Others suggest that the changes are path-dependent (Furstenberg 2013; Fussell 2005; Grant and Furstenberg 2007; Yeung and Alipio 2013; Yeung and Hu 2013). Furthermore, the research in non-Western countries uses diverse indicators to measure the transition to adulthood that hinder comparisons with each other and to Western countries. Life course theory (Elder, Johnson, and Crosnoe 2003) suggests that the meaning of single transitions differs depending on when they occur in the life course, where they fit within a large sequence, and how they vary in a population. Thus it is useful to take a structural view, tracing changes in the timing and sequencing of transitions as well as the distribution of these transitions at the population level.This article provides a structural view of the patterns of change in the transition to adulthood in China from 1982 to 2005. In these years, China experienced massive economic and social transformations with increases in economic uncertainty and individual autonomy (Bramall 2009; Tang and Parish 2000). To trace the changes we use a synthetic cohort approach by comparing the distribution of transitions among census participants aged 18-30 years in four population data sources: the 1982, 1990, and 2000 censuses and the 2005 mini-census. We organize the analyses by subgroups divided by gender and household registration status. In China, the rigid gender division of household labor attaches family transitions to distinct meanings and responsibilities for men and women (Parish and Farrer 2000). The recent and rising gender gap in earnings and promotion opportunities highlights these gender differences (Zhang, Hannum, and Wang 2008). Additionally, by categorizing Chinese populations into two broadly defined groups of urban and rural, household registration status constitutes a key dimension in the Chinese stratification system that is critical for individuals' life chances (Chan 2013; Wu and Treiman 2004; Xie and Zhou 2013).2. Data and methods2.1 Data and measuresThis analysis uses samples from four population data sources: Chinese censuses collected in 1982, 1990, and 2000, and a 2005 mini-census that comprises a 1% sample of the Chinese population. The samples from the 1982 and 1990 censuses are 1% random samples, harmonized by the Integrated Public Use Microdata Series - International project. Our sample from the 2000 census is a .095% random sample and the 2005 mini-census is a 20% random sample. To make the sample sizes comparable, we draw a 10% random sample from the 1982 and 1990 samples. For all four samples, we limit young adults to those between the ages 18 and 30 (Rindfuss 1991).The adulthood transitions are measured in four statuses: school attendance, employment status, marital status, and parental status. Because the parental status was collected exclusively for women, women in our analysis have four statuses and men have three. The four statuses are coded as dichotomous variables that equal 1 if the respondents occupy the status and 0 otherwise2.2.2 MethodsThe analysis is organized by gender and residence (urban or rural). Residence is distinguished by permanent household registration status (hukou).3 Urban residents are measured as those with urban hukou who lived in the registered hukou place at the time of survey. Likewise, rural residents are measured as those with rural hukou who lived in the registered hukou place at the time of the survey. …

The Long-term Impacts of the Cultural Revolution: A Micro-Analysis

This paper provides a micro-analysis of the long-term impacts of a particular historical event: the Cultural Revolution in urban labor market of China. Using the life-cycle models and synthetic cohort approach, I demonstrate that the Cultural Revolution produced a lasting negative effect on permanent income for the subjected birth cohorts and this effect was amplified from the middle 1990s to the early 2000s as the Chinese market economy increasingly evolved. Channels in the mechanism of the impact includes productivity determinants (educational attainment, work experience, and health), marriage, and personality. The conclusions are robust to a variety of controls for family background as well as contamination factors, examinations with various control groups, contemporaneous comparisons, and placebo tests.

Education and Lifetime Earnings in the United States.

Differences in lifetime earnings by educational attainment have been of great research and policy interest. Although a large literature examines earnings differences by educational attainment, research on lifetime earnings--which refers to total accumulated earnings from entry into the labor market until retirement--remains limited because of the paucity of adequate data. Using data that match respondents in the Survey of Income and Program Participation to their longitudinal tax earnings as recorded by the Social Security Administration, we estimate the 50-year work career effects of education on lifetime earnings for men and women. By overcoming the purely synthetic cohort approach, our results provide a more realistic appraisal of actual patterns of lifetime earnings. Detailed estimates are provided for gross lifetime earnings by education; net lifetime earnings after controlling for covariates associated with the probability of obtaining a bachelor's degree; and the net present 50-year lifetime value of education at age 20. In addition, we provide estimates that include individuals with zero earnings and disability. We also assess the adequacy of the purely synthetic cohort approach, which uses age differences in earnings observed in cross-sectional surveys to approximate lifetime earnings. Overall, our results confirm the persistent positive effects of higher education on earnings over different stages of the work career and over a lifetime, but also reveal notably smaller net effects on lifetime earnings compared with previously reported estimates. We discuss the implications of these and other findings.

Age-specific changes in BMI and BMI distribution among Australian adults using cross-sectional surveys from 1980 to 2008.

Research efforts have focused mainly on trends in obesity among populations, or changes in mean body mass index (BMI), without consideration of changes in BMI across the BMI spectrum. Examination of age-specific changes in BMI distribution may reveal patterns that are relevant to targeting of interventions. Using a synthetic cohort approach (which matches members of cross-sectional surveys by birth year) we estimated population representative annual BMI change across two time periods (1980 to 1989 and 1995 to 2008) by age, sex, socioeconomic position and quantiles of BMI. Our study population was a total of 27349 participants from four nationally representative Australian health surveys; Risk Factor Prevalence Study surveys (1980 and 1989), the 1995 National Nutrition Survey and the 2007/8 National Health Survey. We found greater mean BMI increases in younger people, in those already overweight and in those with lower education. For men, age-specific mean annual BMI change was very similar in the 1980s and the early 2000s (P=0.39), but there was a recent slowing down of annual BMI gain for older women in the 2000s compared with their same-age counterparts in the 1980s (P<0.05). BMI change was not uniform across the BMI distribution, with different patterns by age and sex in different periods. Young adults had much greater BMI gain at higher BMI quantiles, thus adding to the increased right skew in BMI, whereas BMI gain for older populations was more even across the BMI distribution. The synthetic cohort technique provided useful information from serial cross-sectional survey data. The quantification of annual BMI change has contributed to an understanding of the epidemiology of obesity progression and identified key target groups for policy attention-young adults, those who are already overweight and those of lower socioeconomic status.

Impact of Oil Boom and Bust on Human Capital Investment in the U.S.

This paper uses Census IPUMS data from 1970 to 2000 and ACS data from 2010 to estimate the impact of the oil boom and bust on wages and human capital formation in the US. The paper finds that the oil boom between 1970 and 1980 was associated with a slower growth in the relative demand for skills in the oil and gas sector and regions where the sector had a large presence. Overall, the oil boom led to a sharp rise in real wages in oil areas relative to non-oil parts of the nation, raising the opportunity cost of additional schooling. Real wage premium for a college degree declined during the oil boom in oil-rich regions such as Texas, compared with non-oil areas. The oil boom of the 1970’s potentially had an impact on human capital investment through two channels — by raising the opportunity cost of additional schooling as well as by lowering the returns from going to college. Using a synthetic cohort approach the paper finds that relative to cohorts who went to high school in the pre-boom period, the cohort reaching high school age during the oil boom was about 2 percentage points less likely to have a college degree by the time they turned 34 to 37 years of age in 2000.

Lifetime conviction risk—a synthetic cohort approach

How common are convictions? The stigma of a criminal record can have serious social and financial consequences for the individual. It is a fundamental question in relation to any policy how many people will be affected by it. For example, if it is desirable to make sentencing generally stricter, or restrict ex-offenders' employment opportunities, how many people will that apply to? Little is known about how many people acquire a criminal record over their life-course. In this paper, I apply life-table methods to a synthetic cohort to calculate the lifetime conviction risk. The findings show that a substantial proportion of the population will be convicted of a crime at some point. Not surprisingly, the figures for men are substantially higher than for women.

Consumption Patterns Among Aging Canadians: A Synthetic Cohort Approach

Studies of pre- and post-retirement annual income have focused on the extent to which income falls at this crucial stage in life. Although these studies vary in scope and intent, the overall consensus is that the Canadian retirement income system provides income replacement rates that are in the excess of 60% to 70% for a plurality of Canadians, especially for those who had low incomes during their prime working years. However, little has been published on the extent to which retirees maintain their same levels of consumption. Using data from the Survey of Family Expenditures (FAMEX) and from the Survey of Household Spending (SHS), this study develops a synthetic cohort approach to determine how the consumption patterns of households headed by individuals in their late 40s (in the early 1980s) differ from those of a group of households headed by individuals in their early 70s (in the late 2000s). It finds that, even though the nature of consumption changes over time, the overall levels of consumption “per adult” do not decline by substantial amounts among Canadians as they age.

Labour Market Outcomes for Immigrants in New Zealand

This paper uses data from the 1997-2007 New Zealand Income Survey to examine the labour market performance of immigrants in New Zealand. Specifically, we use a synthetic cohort approach to examine how employment rates and hourly wages for immigrants compare to those for the New Zealand-born. Extending previous work, we examine how outcomes for immigrants change with years spent in New Zealand in a semi-parametric manner that makes no assumptions about how labour market outcomes evolve as more host country experience is acquired. The pattern of entry disadvantage followed by subsequent relative improvement is more pronounced for employment rates than for wage rates.

Immigrant-Native Fertility and Mortality Differentials in the United States

Immigrants have been discussed as a means of alleviating fiscal pressures on Social Security. Their long-term impact on the Social Security system depends critically on their fertility and mortality patterns. In this paper, we examine the fertility and mortality patterns of immigrants to the United States and compare these patterns with those of non-immigrants. We find that both the recent and cumulative fertility of immigrant women is higher than that of native-born women, but that a large share of these differentials can be explained by differences in age structures, race and ethnicity, years in the United States, and country of origin. Using a synthetic cohort approach, we examine the role of years in the United States in more detail, and find no evidence of assimilation towards native-born fertility patterns. Consistent with previous research, we find evidence of a disruption effect on fertility - the fertility of immigrant women in the most recent arrival cohorts is low, but increases at a faster rate relative to both the fertility of immigrants from earlier cohorts and relative to the fertility of natives. We find that immigrants experience lower mortality than native-born individuals in the United States, and these differences remain even after controlling for underlying differences in observable characteristics. However we find that they do not exhibit differences in their subjective expectations of their mortality.

Development of Cardiovascular Risk Factors From Ages 8 to 18 in Project HeartBeat!

Project HeartBeat! is a longitudinal study of the development of cardiovascular risk factors as growth processes. Patterns of serial change, or trajectories, from ages 8 to 18 years for plasma total cholesterol concentration (TC) and percent body fat illustrate the design and synthetic cohort approach of the study. Six hundred seventy-eight children (49.1% female, 20.1% black) entered the study at ages 8, 11, and 14 years and were followed up with examinations every 4 months for < or = 4 years. Multilevel analysis demonstrated trajectories for population mean values of TC and percent body fat in sex-specific synthetic cohorts from ages 8 to 18 years. Polyphasic patterns of change in TC were confirmed, with notable sex differences in age patterns and with minimum mean values of TC of 3.85 mmol/L for females and 3.59 for males. As illustrated by data for males, the approximate 75th percentile values of mean TC ranged from 4.78 mmol/L at its early peak to 4.06 at its late-teen nadir. Percent body fat exhibited a trajectory closely parallel with that for TC only for males and appeared to be unrelated for females. The polyphasic trajectory for TC from ages 8 to 18 years differs between females and males, indicates marked age variation in 75th percentile values and, in males only, closely parallels the trajectory for percent body fat. These and other results indicate the value of both follow-up every 4 months across age intervals to detect rapid risk factor change and the synthetic cohort approach for gaining new insights into the dynamics and possible determinants of this change from ages 8 to 18 years.