Sibling Correlations Research Articles

Class origin and sibling similarities in long-term income

Sibling correlations have gained increasing prominence in inequality studies as a measurement of the total impact of family background on individual outcomes. Whilst previous studies have tended to use traditional socio-economic measures such as parent’s income or education, this paper introduces an analytical class approach to sibling studies by analysing how much of the influence that siblings share in their long-term income results from class origin. Data are from Statistics Denmark and consist of 290,399 individuals born between 1963 and 1973. Models are estimated which – in addition to parents’ education and income – include modifications of the Erikson–Goldthorpe–Portocarero schemes ranging from 3 to 15 classes and Grusky’s micro-class scheme of 72 classes. The results show that although class adds to explanations of the family influence on children’s income, most of the sibling similarities are not explained by parental education, income or class. Depending on gender, the class schemes explain between 8 and 13 per cent of the sibling similarities and 15 to 20 per cent when parents’ income and educations are also included. Models with different class schemes demonstrate that elaborated versions of the EGP class scheme add little to the explanation of similarities between brothers, sisters and mixed siblings.

A Longitudinal Adoption Study of Substance Use Behavior in Adolescence.

Although cross-sectional twin studies have assessed the genetic and environmental etiologies of substance use during adolescence and early adulthood, comparisons of results across different samples, measures, and cohorts are problematic. While several longitudinal twin studies have investigated these issues, few corroborating adoption studies have been conducted. The current study is the first to estimate the magnitude of genetic, shared environmental, and non-shared environmental influences on substance use (cigarettes, alcohol, and marijuana) from ages 14 to 18 years, using a prospective longitudinal adoption design. Adoptive and control sibling correlations provided substantial evidence for early genetic effects on cigarette, alcohol, and marijuana use/no use. Shared environmental effects were relatively modest, except for alcohol use, which showed increases in late adolescence (age 17 to 18 years). Sibling similarity for quantity/frequency of use also support additive genetic influences across adolescence, with some shared environmental influences for all three substances. To test the stability of these influences across time, a series of independent pathway models were run to explore common and age-specific influences. For all substances, there were minimal age-specific additive genetic and shared environmental influences on quantity/frequency of use. Further, there was a trend toward increasing genetic influences on cigarette and alcohol use across ages. Genetic influences on marijuana were important early, but did not contribute substantially at age 17 and 18 years. Overall, the findings indicate that genetic influences make important contributions to the frequency/quantity of substance use in adolescence, and suggest that new genetic influences may emerge in late adolescence for cigarette and alcohol use.

Cognitive Skills, Non-Cognitive Skills, and Family Background: Evidence from Sibling Correlations

This paper estimates sibling correlations in cognitive and non-cognitive skills to evaluate the importance of family background for skill formation. Based on a large representative German dataset including IQ test scores and measures of non-cognitive skills, a restricted maximum likelihood model indicates a strong relationship between family background and skill formation. Sibling correlations in non-cognitive skills range from 0.22 to 0.46; therefore, at least one-fifth of the variance in these skills results from shared sibling-related factors. Sibling correlations in cognitive skills are higher than 0.50; therefore, more than half of the inequality in cognition can be explained by shared family background. Comparing these findings with those in the intergenerational skill transmission literature suggests that intergenerational correlations capture only part of the influence of family on children's cognitive and non-cognitive skills, as confirmed by decomposition analyses and in line with previous findings on educational and income mobility.

Inequalities in Educational Outcomes: How Important is the Family?

In this paper, we investigate sibling correlations in educational outcomes, which serve as a broad measure of the importance of family and community background. Making use of rich longitudinal survey and register data for Denmark, our main aim is to identify the parental background characteristics that are able to explain the resemblance in educational outcomes among siblings. We find sibling correlations in educational outcomes in the range of 15 to 33 percent, suggesting that up to a third of the variation in educational achievement can be explained by family and community background. Our results further reveal that parents' socio-economic background can account for a large part of the sibling correlation. Other family characteristics such as family structure, the incidence of social problems, and parents' educational preferences also play a role, though these factors only contribute to explaining sibling similarities at lower levels of the educational distribution.

The Chips are Down: The Influence of Family on Children's Trust Formation

Understanding the formation of trust at the individual level is a key issue given the impact that it has been recognised to have on economic development. Theoretical work highlights the role of the transmission of values such as trust from parents to their children. Attempts to empirically measure the strength of this transmission relied so far on the cross-sectional regression of the trust of children on the contemporaneous trust of their parents. We introduce a new identification strategy which hinges on a panel of parents and their children drawn from the German Socio-Economic Panel. Our results show that: 1) a half to two thirds of the observed variability of trust is pure noise irrelevant to the transmission process; 2) this noise strongly biases the parameter estimates of the OLS regression of children's trust on parents' trust; however an instrumental variable procedure straightforwardly emerges from the analysis; 3) the dynamics of the component of trust relevant to the transmission process shed light on the structural interpretation of the parameters of this regression; 4) the strength of the flow of trust that parents pass to their children as well as of the sibling correlations due to other factors are easily summarised by the conventional R2 of a latent equation. In our sample, approximately one fourth of the variability of children's trust is inherited from their parents while two thirds are attributable to the residual sibling correlation.

On the Origins of Entrepreneurship: Evidence from Sibling Correlations

Promoting entrepreneurship has become an increasingly important part of the policy agenda in many countries. The success of such policies, however, rests in part on the assumption that entrepreneurship outcomes are not fully determined at a young age by factors that are unrelated to current policy. We test this assumption and assess the importance of family background and neighborhood effects as determinants of entrepreneurship, by estimating sibling correlations in entrepreneurship. We find that between 20 and 50 percent of the variance in different entrepreneurial outcomes is explained by factors that siblings share (i.e., family background and neighborhood effects). The average is 28 percent. Hence, entrepreneurship is far less than fully determined at a young age. Our estimates increase only a little when allowing for differential treatment within families by gender and birth order. We then investigate a comprehensive set of mechanisms that explain sibling similarities. Parental entrepreneurship plays a large role in explaining sibling similarities, as do shared genes. We show that neighborhood effects matter, but are rather small, particularly when compared with the overall importance of family factors. Sibling peer effects, and parental income and education matter even less.

OBSESSIVE-COMPULSIVE PERSONALITY DISORDER: EVIDENCE FOR TWO DIMENSIONS.

To determine possible dimensions that underlie obsessive-compulsive personality disorder (OCPD) and to investigate their clinical correlates, familiality, and genetic linkage. Participants were selected from 844 adults assessed with the Structured Instrument for the Diagnosis of DSM-IV Personality Disorders (SIDP) in the OCD Collaborative Genetics Study (OCGS) that targeted families with obsessive-compulsive disorder (OCD) affected sibling pairs. We conducted an exploratory factor analysis, which included the eight SIDP-derived DSM-IV OCPD traits and the indecision trait from the DSM-III, assessed clinical correlates, and estimated sib-sib correlations to evaluate familiality of the factors. Using MERLIN and MINX, we performed genome-wide quantitative trait locus (QTL) linkage analysis to test for allele sharing among individuals. Two factors were identified: Factor 1: order/control (perfectionism, excessive devotion to work, overconscientiousness, reluctance to delegate, and rigidity); and Factor 2: hoarding/indecision (inability to discard and indecisiveness). Factor 1 score was associated with poor insight, whereas Factor 2 score was associated with task incompletion. A significant sib-sib correlation was found for Factor 2 (rICC = .354, P < .0001) but not Factor 1 (rICC = .129, P = .084). The linkage findings were different for the two factors. When Factor 2 was analyzed as a quantitative trait, a strong signal was detected on chromosome 10 at marker d10s1221: KAC LOD = 2.83, P = .0002; and marker d10s1225: KAC LOD = 1.35, P = .006. The results indicate two factors of OCPD, order/control and hoarding/indecision. The hoarding/indecision factor is familial and shows modest linkage to a region on chromosome 10.

Association Analysis of FOXO3 Longevity Variants With Blood Pressure and Essential Hypertension.

The minor alleles of 3 FOXO3 single nucleotide polymorphisms (SNPs)- rs2802292 , rs2253310 , and rs2802288 -are associated with human longevity. The aim of the present study was to test these SNPs for association with blood pressure (BP) and essential hypertension (EHT). In a primary study involving Americans of Japanese ancestry drawn from the Family Blood Pressure Program II we genotyped 411 female and 432 male subjects aged 40-79 years and tested for statistical association by contingency table analysis and generalized linear models that included logistic regression adjusting for sibling correlation in the data set. Replication of rs2802292 with EHT was attempted in Japanese SONIC study subjects and of each SNP in a meta-analysis of genome-wide association studies of BP in individuals of European ancestry. In Americans of Japanese ancestry, women homozygous for the longevity-associated (minor) allele of each FOXO3 SNP had 6mm Hg lower systolic BP and 3mm Hg lower diastolic BP compared with major allele homozygotes (Bonferroni corrected P < 0.05 and >0.05, respectively). Frequencies of minor allele homozygotes were 3.3-3.9% in women with EHT compared with 9.5-9.6% in normotensive women ( P = 0.03-0.04; haplotype analysis P = 0.0002). No association with BP or EHT was evident in males. An association with EHT was seen for the minor allele of rs2802292 in the Japanese SONIC cohort ( P = 0.03), while in European subjects the minor allele of each SNP was associated with higher systolic and diastolic BP. Longevity-associated FOXO3 variants may be associated with lower BP and EHT in Japanese women.

Are We Architects of Our Own Happiness? The Importance of Family Background for Well-Being

Abstract This paper analyzes whether individuals have equal opportunity to achieve happiness (or well-being). We estimate sibling correlations and intergenerational correlations in self-reported life satisfaction, satisfaction with household income, job satisfaction, and satisfaction with health. We find high sibling correlations for all measures of well-being. The results suggest that family background explains, on average, between 30% and 60% of the inequality in permanent well-being. The influence is smaller when the siblings’ psychological and geographical distance from their parental home is larger. Results from intergenerational correlations suggest that parental characteristics are considerably less important than family and community factors.

The importance of family background and neighborhood effects as determinants of crime

We quantify the importance of family background and neighborhood effects as determinants of criminal convictions and incarceration by estimating sibling correlations. At the extensive margin, factors common to siblings account for 24 % of the variation in criminal convictions and 39 % of the variation in incarceration. At the intensive margin, these factors typically account for slightly less than half of the variation in prison sentence length and between one third and one half of the variation in criminal convictions, depending on crime type and gender. Further analysis shows that parental criminality and family structure can account for more of the sibling crime correlation than parental income and education or neighborhood characteristics. The lion’s share of the sibling correlation, however, is unaccounted for by these factors. Finally, sibling spacing also matters—more closely spaced siblings are more similar in their criminal behavior.

Psychiatric disorders in child and adolescent offspring of patients with schizophrenia and bipolar disorder: A controlled study

BackgroundEarly clinical manifestations predating schizophrenia (SZ) and bipolar disorder (BP) have not been fully characterized. Child offspring studies are a valuable opportunity to study the natural history of the illness from its earliest stages. However, there is limited evidence assessing young offspring of SZ and BP simultaneously. We set out to assess rates of psychiatric disorders in child and adolescent offspring of SZ and BP, relative to offspring of community controls, so as to characterize the early phenotype of the disorders comparatively. MethodsSZ and BP parents with offspring aged 7–17years were recruited through adult mental health services of two tertiary hospitals. Community control (CC) parents were recruited from the same geographical area. Ninety BP-offspring, 41 SZ-offspring and 107 CC-offspring were assessed using the K-SADS-PL by child psychiatrists blinded to parental status. Differences in prevalence of psychiatric disorders between groups were adjusted for confounders and for sibling correlation using generalised estimating equations. ResultsWe found a gradient of clinical severity and social disadvantage between SZ, BP and CC-offspring. After adjusting for socio-demographic confounders, SZ and BP-offspring presented higher rates of attention deficit hyperactivity disorder (ADHD) than CC-offspring. ADHD was more prevalent in SZ-offspring than BP-offspring, and BP-offspring presented a higher prevalence of depression than CC-offspring. ConclusionsThe higher rates of ADHD in SZ-offspring suggest that abnormal neurodevelopmental processes may exert a stronger influence in SZ than BP. Follow-up of these children will help elucidate the role of ADHD and depression phenotypes in predicting future transition to SZ or BP.

Gender, Geography, and Generations: Intergenerational Educational Mobility in Post-Reform India

India experienced sustained economic growth for more than two decades following the economic liberalization in 1991. While economic growth reduced poverty significantly, it was associated with an increase in inequality. Does this increase in inequality reflect deep-seated inequality of opportunity or efficient incentive structure in a market oriented economy? This paper provides evidence on economic mobility in post-reform India by focusing on the educational attainment of children. It uses two related measures of immobility: sibling and intergenerational correlations. The paper analyzes the trends in and patterns of educational mobility from 1992/93 to 2006, with a special emphasis on the roles played by gender and geography. The evidence shows that family background plays a strong role; the estimated sibling correlation in India in 2006 is higher than the available estimates for Latin American countries. There is a persistent gender gap in rural and less-developed areas. The only group that experienced substantial improvements is women in urban and developed areas, with the lower caste women benefiting the most. Almost 70 percent of the variance in children's education can be accounted for by parental education and geographic location. The authors provide possible explanations for the apparently puzzling improvements for urban women in a country with strong son preference.

Comparing Overall Effects of Family Background on Homeownership During Early Life Course

This paper considers the overall effect of family background on homeownership by applying sibling correlation models. Sex differences, differences between singles and couples, and variation during the early life course (25–35 years old) are analysed using Finnish register data. These models enable the estimation of the overall effect of the family background, irrespective of identifying mechanisms behind these effects. The results indicate that family background has a significant effect, explaining around 11 per cent of the variation in the probability of homeownership. The effects for men living without a partner were significantly higher than for men living with a partner: around 24 per cent and 12 per cent, respectively. No corresponding difference for women could be established. These findings suggest that the effect of family background on homeownership is, in general, high and especially so for single men.

Metabolic factors and genetic risk mediate familial type 2 diabetes risk in the Framingham Heart Study.

Type 2 diabetes mellitus in parents is a strong determinant of diabetes risk in their offspring. We hypothesise that offspring diabetes risk associated with parental diabetes is mediated by metabolic risk factors. We studied initially non-diabetic participants of the Framingham Offspring Study. Metabolic risk was estimated using beta cell corrected insulin response (CIR), HOMA-IR or a count of metabolic syndrome components (metabolic syndrome score [MSS]). Dietary risk and physical activity were estimated using questionnaire responses. Genetic risk score (GRS) was estimated as the count of 62 type 2 diabetes risk alleles. The outcome of incident diabetes in offspring was examined across levels of parental diabetes exposure, accounting for sibling correlation and adjusting for age, sex and putative mediators. The proportion mediated was estimated by comparing regression coefficients for parental diabetes with (β adj) and without (β unadj) adjustments for CIR, HOMA-IR, MSS and GRS (percentage mediated = 1 - β adj / β unadj). Metabolic factors mediated 11% of offspring diabetes risk associated with parental diabetes, corresponding to a reduction in OR per diabetic parent from 2.13 to 1.96. GRS mediated 9% of risk, corresponding to a reduction in OR per diabetic parent from 2.13 to 1.99. Metabolic risk factors partially mediated offspring type 2 diabetes risk conferred by parental diabetes to a similar magnitude as genetic risk. However, a substantial proportion of offspring diabetes risk associated with parental diabetes remains unexplained by metabolic factors, genetic risk, diet and physical activity, suggesting that important familial influences on diabetes risk remain undiscovered.

The Psychometric and Empirical Properties of Measures of Risk Preferences

We conduct a detailed examination of the psychometric and empirical properties of some commonly used survey-based measures of risk preferences in a population-based sample of 11,000 twins. Using a model that provides a general framework for making inferences about the component of measured risk attitudes that is not due to measurement error, we show the measurement-error adjustment leads to substantially larger estimates of the predictive power of risk attitudes, of the size of the gender gap, and of the magnitude of the sibling correlation. Risk attitudes are predictive of investment decisions, entrepreneurship, and health behaviors such as smoking and drinking, are robustly associated with cognitive ability and personality, and our estimates are often larger than those in the literature. One implication of our results is that the small amounts of variation that the risk measures have previously been reported to explain are in part artifacts of imperfect measurement.

The Informational Content of Surnames, the Evolution of Intergenerational Mobility, and Assortative Mating

We propose a new methodology for measuring intergenerational mobility in economic well-being. Our method is based on the joint distribution of surnames and economic outcomes. It circumvents the need for intergenerational panel data, a long-standing stumbling block for understanding mobility. It does so by using cross-sectional data alongside a calibrated structural model to recover the traditional intergenerational elasticity measures. Our main idea is simple. If “inheritance” is important for economic outcomes, then rare surnames should predict economic outcomes in the cross-section. This is because rare surnames are indicative of familial linkages. If the number of rare surnames is small this approach will not work. However, rare surnames are abundant in the highly skewed nature of surname distributions from most Western societies. We develop a model that articulates this idea and shows that the more important is inheritance, the more informative will be surnames. This result is robust to a variety of different assumptions about fertility and mating. We apply our method using the 2001 census from Catalonia, a large region of Spain. We use educational attainment as a proxy for overall economic well-being. A calibration exercise results in an estimate of the intergenerational correlation of educational attainment of 0.60. We also find evidence suggesting that mobility has decreased among the different generations of the 20th century. A complementary analysis based on sibling correlations confirms our results and provides a robustness check on our method. Our model and our data allow us to examine one possible explanation for the observed decrease in mobility. We find that the degree of assortative mating has increased over time. Overall, we argue that our method has promise because it can tap the vast mines of census data that are available in a heretofore unexploited manner.

Adolescent outcomes and opportunities in a Canadian province: looking at siblings and neighbors.

BackgroundWell-organized administrative data with large numbers of cases (building on linked files from several government departments) and a population registry facilitate new studies of population health and child development. Analyses of family relationships and a number of outcomes--educational achievement, health, teen pregnancy, and receipt of income assistance--are relatively easy to conduct using several birth cohorts. Looking both at means/proportions and at sibling correlations enriches our study of opportunity and well-being in late adolescence. With observational research possibly exaggerating the causal effects of risk factors, sibling comparisons involving individuals sharing both many family characteristics and many genes help deal with such criticisms.MethodsThis paper uses a rich dataset from one Canadian province (Manitoba) covering a wide range of geographical areas (cities to rural regions). Influences on opportunity and well-being are analyzed looking at both means/proportions and sibling correlations. We measure a variety of outcomes that may reflect different causal influences. A creative application of linear programming advances the use of data on residential location.ResultsPredicting educational achievement using available variables was much easier than predicting adolescent health status (R-square of .200 versus R-square of .043). Low levels of educational achievement, high levels of teenage pregnancy, and high sibling correlations outside Winnipeg and within Winnipeg’s lower income areas highlight inequalities across socioeconomic and geographic backgrounds. Stratifying our analyses by different variables, such as income quintiles, reveals differences in means and correlations within outcomes and across groups. Particular events--changes in mother’s marital status and in place of residence--were associated with less favorable outcomes in late adolescence.ConclusionOur findings suggest a paradox: Canadian developmental outcomes through late adolescence appear quite similar to those in the United States, even though intergenerational mobility in Canada is closer to mobility in the Nordic countries than to that in the United States.

An Analysis of Sibling Correlations in Health Using Latent Variable Models

We investigate sibling correlations in health status using the Panel Study of Income Dynamics and Bayesian methods that allow us to estimate the covariance structure of a system of latent variable equations. Across a battery of outcomes, we estimate that between 50% and 60% of health status can be attributed to familial or neighborhood characteristics. Taking the principal component across all outcomes, we obtain a sibling correlation of about 53%. These estimates, which are larger than previous estimates of sibling correlations in health that rely on linear models, are more in-line with sibling correlations in income and suggest that health status, like other measures of socioeconomic success, is strongly influenced by family background. Therefore, efforts to improve the circumstances of families and communities may potentially lead to improved childhood health today and also reduce future health disparities.

Adolescent Outcomes and Opportunities in a Canadian Province: Looking at Siblings and Neighbors

BACKGROUND: Well-organized administrative data with large numbers of cases (building on linked files from several government departments) and a population registry facilitate new studies of population health and child development. Analyses of family relationships and a number of outcomes -- educational achievement, health, teen pregnancy, and receipt of income assistance -- are relatively easy to conduct using several birth cohorts. Looking both at means/proportions and at sibling correlations enriches our study of opportunity and well-being in late adolescence. With observational research possibly exaggerating the causal effects of risk factors, sibling comparisons involving individuals sharing both many family characteristics and many genes help deal with such criticisms. METHODS: This paper uses a rich dataset from one Canadian province (Manitoba) covering a wide range of geographical areas (cities to rural regions). Influences on opportunity and well-being are analyzed looking at both means/proportions and sibling correlations. We measure a variety of outcomes that may reflect different causal influences. A creative application of linear programming advances the use of data on residential location. RESULTS: Predicting educational achievement using available variables was much easier than predicting adolescent health status (R-square of .200 versus R-square of .043). Low levels of educational achievement, high levels of teenage pregnancy, and high sibling correlations outside Winnipeg and within Winnipeg's lower income areas highlight inequalities across socioeconomic and geographic backgrounds. Stratifying our analyses by different variables, such as income quintiles, reveals differences in means and correlations within outcomes and across groups. Particular events -- changes in mother's marital status and in place of residence -- were associated with less favorable outcomes in late adolescence. CONCLUSION: Our findings suggest a paradox: Canadian developmental outcomes through late adolescence appear quite similar to those in the United States, even though intergenerational mobility in Canada is closer to mobility in the Nordic countries than to that in the United States.

Autism traits in the RASopathies

BackgroundMutations in Ras/mitogen-activated protein kinase (Ras/MAPK) pathway genes lead to a class of disorders known as RASopathies, including neurofibromatosis type 1 (NF1), Noonan syndrome (NS), Costello syndrome (CS), and cardio-facio-cutaneous...