Achievement and social mobility: Relationships among IQ score,education, and occupation in two generations

Abstract

A study of males and their fathers representative of the nonfarm white population of Minnesota supports the hypothesis that social mobility is correlated with the discrepancies between the general intelligence of sons, as measured by IQ test scores, and the social class into which they were born. A multiple regression analysis performed on these data illustrates the independent contribution of intelligence to the variance in two achieved statuses, educational attainment and occupational level. The substantial correlation between father‐son difference in IQ score and father‐son difference in social position, and the relationship between the magnitude and direction of IQ score difference and the distance and direction of social mobility, both support the view that differences in ability provide a “springboard” that enables individuals to be socially mobile and that to some degree prevents social classes in an open society from congealing into castes.     

Genome‐wide association study of word reading: Overlap with risk genes for neurodevelopmental disorders

Reading disabilities (RD) are the most common neurocognitive disorder, affecting 5% to 17% of children in North America. These children often have comorbid neurodevelopmental/psychiatric disorders, such as attention deficit/hyperactivity disorder (ADHD). The genetics of RD and their overlap with other disorders is incompletely understood. To contribute to this, we performed a genome‐wide association study (GWAS) for word reading. Then, using summary statistics from neurodevelopmental/psychiatric disorders, we computed polygenic risk scores (PRS) and used them to predict reading ability in our samples. This enabled us to test the shared aetiology between RD and other disorders. The GWAS consisted of 5.3 million single nucleotide polymorphisms (SNPs) and two samples; a family‐based sample recruited for reading difficulties in Toronto (n = 624) and a population‐based sample recruited in Philadelphia [Philadelphia Neurodevelopmental Cohort (PNC)] (n = 4430). The Toronto sample SNP‐based analysis identified suggestive SNPs (P ~ 5 × 10^?7) in the ARHGAP23 gene, which is implicated in neuronal migration/axon pathfinding. The PNC gene‐based analysis identified significant associations (P < 2.72 × 10^?6) for LINC00935 and CCNT1, located in the region of the KANSL2/CCNT1/LINC00935/SNORA2B/SNORA34/MIR4701/ADCY6 genes on chromosome 12q, with near significant SNP‐based analysis. PRS identified significant overlap between word reading and intelligence (R² = 0.18, P = 7.25 × 10^?181), word reading and educational attainment (R² = 0.07, P = 4.91 × 10^?48) and word reading and ADHD (R² = 0.02, P = 8.70 × 10^?6; threshold for significance = 7.14 × 10^?3). Overlap was also found between RD and autism spectrum disorder (ASD) as top‐ranked genes were previously implicated in autism by rare and copy number variant analyses. These findings support shared risk between word reading, cognitive measures, educational outcomes and neurodevelopmental disorders, including ASD.     

Performance IQ in children is associated with blood cadmium concentration in early pregnancy

ObjectiveTo investigate whether performance IQ in children is associated with maternal blood cadmium concentration in early pregnancy.MethodThe present study is a component of the Mothers’ and Children's Environmental Health (MOCEH) study, a multi-center birth cohort project in Korea that began in 2006. The study cohort consisted of 119 children whose mothers underwent testing of blood cadmium during early pregnancy. All children were evaluated using the Korean version of the Wechsler Preschool and Primary Scale of Intelligence, revised edition (WPPSI-R), at 60 months of age. Multivariate linear regression analysis was performed to analyze the correlation between IQ in children and maternal blood cadmium concentration in early pregnancy, after adjustment for covariates.ResultsMaternal blood cadmium concentration during early pregnancy was inversely associated with performance IQ, after adjustment for covariates such as sex, educational levels of both parents, family income, and maternal BMI. Maternal blood cadmium concentration, however, was not associated with cognitive IQ.ConclusionPerformance IQ in children is associated with maternal blood cadmium concentration in early pregnancy.     

Effect of number and position of siblings on child and adult outcomes

Abstract

In this paper we consider how family size and birth order may affect educational attainment and earnings. Family size may be important because if more children have to share parental financial, emotional, and time resources, each child may get less. Birth order may be important because of differences in endowments, parental resources over the life cycle, or parental preferences. We demonstrate how these different factors interact in a particular model.

Empirically we find both birth‐order and family‐size effects for schooling even when controlling for parental age, income, and education and father's religion. These effects are bigger for daughters than sons. Using the same controls, we do not find statistically significant family‐size or birth‐order effects for the In of earnings in a relatively young sample. We also present equations for how college was financed. Family size cuts down parental contribution per child and encourages working, scholarship, and loans. Results differ somewhat for sons and daughters.     

Validation of BIA in Obese Children and Adolescents and Re‐evaluation in a Longitudinal Study

Decrease in fat mass (FM) is a one of the aims of pediatric obesity treatment; however, measurement techniques suitable for routine clinical assessment are lacking. The objective of this study was to validate whole‐body bioelectrical impedance analysis (BIA; TANITA BC‐418MA) against the three‐component (3C) model of body composition in obese children and adolescents, and to test the accuracy of our new equations in an independent sample studied longitudinally. A total of 77 white obese subjects (30 males) aged 5–22 years, BMI‐standard deviation score (SDS) 1.6–3.9, had measurements of weight, height (HT), body volume, total body water (TBW), and impedance (Z). FM and fat‐free mass (FFM) were calculated using the 3C model or predicted from TANITA. FFM was predicted from HT²/Z. This equation was then evaluated in 17 other obese children (5 males) aged 9–13 years. Compared to the 3C model, TANITA manufacturer's equations overestimated FFM by 2.7 kg (P < 0.001). We derived a new equation: FFM = ?2.211 + 1.115 (HT²/Z), with r² of 0.96, standard error of the estimate 2.3 kg. Use of this equation in the independent sample showed no significant bias in FM or FFM (mean bias 0.5 ± 2.4 kg; P = 0.4), and no significant bias in change in FM or FFM (mean bias 0.2 ± 1.8 kg; P = 0.7), accounting for 58% (P < 0.001) and 55% (P = 0.001) of the change in FM and FFM, respectively. Our derived BIA equation, shown to be reliable for longitudinal assessment in white obese children, will aid routine clinical monitoring of body composition in this population.     

Low educational attainment is still associated with late melanoma diagnosis: A cross-sectional study from a European setting with universal healthcare

BackgroundAn early diagnosis of cutaneous melanoma remains determinant for improved survival. Low educational attainment has been associated with a late-stage diagnosis in settings where access to healthcare is restricted. Little evidence is available from regions with universal healthcare. We aimed at analysing whether educational attainment was associated with Breslow thickness at diagnosis in a peripheral European region with universal healthcare (in the Canary Islands, Spain).MethodsWe conducted a cross-sectional study with prospectively collected data (2010–2017). Patients were recruited at diagnosis, and information about Breslow thickness, age at diagnosis, gender, highest educational attainment and site of melanoma were registered. Univariate and multivariate linear regression analyses were performed.ResultsLow educational attainment was associated with thicker tumours at diagnosis. The association remained true after adjustment for age, gender and site of melanoma. In the multivariate analysis, tumours diagnosed in patients with low educational attainment were on average 1.08 mm thicker (95% confidence interval: 0.36–1.81; p = 0.003) than those diagnosed in patients with high educational attainment.ConclusionPublic health strategies targeting this vulnerable group are currently needed in the Canary Islands (Spain).     

Maternal feeding strategies, child eating behaviors, and child BMI in low-income African-American preschoolers

Objective: To test the hypothesis that low‐income African‐American preschool children would have a higher BMI if their mothers reported greater “restriction” and “control” in feeding and if mothers reported that children showed greater “food responsiveness” and “desire to drink.” In addition, to test whether higher maternal “pressure to eat” would be associated with lower child BMI. Research Methods and Procedures: A questionnaire was completed by 296 low‐income African‐American mothers of preschool children. It assessed three constructs on maternal feeding strategies (“restriction,” “pressure to eat,” and “control”) and two on child eating behaviors (“food responsiveness” and “desire to drink”). Children's BMI was measured, and mothers’ BMI was self‐reported. Results: The mean (standard deviation) BMI z‐score of the children was 0.34 (1.5), and 44% of the mothers were obese (BMI ≥30 kg/m²). Only maternal “pressure to eat” had a significant overall association with child BMI z‐score (r = ?0.16, p < 0.01). Both maternal “restriction” and “control” were positively associated with children's BMI z‐score in the case of obese mothers (r = 0.20, p = 0.03 and r = 0.24, p = 0.007, respectively), but this was not so in the case of non‐obese mothers (r = ?0.16, p = 0.05 and r = ?0.07, p = 0.39, respectively). Discussion: Among low‐income African Americans, the positive association between maternal restriction and control in feeding and their preschoolers’ BMI was limited to obese mothers. Relations between parent feeding strategies and child weight status in this population may differ on the basis of maternal weight status.     

Social and biological determinants of age at first marriage in Taiwan, 1970

Abstract

This study examines the social and biological determinants of age at first marriage in two townships in northern Taiwan, one very rural and traditional and the other urban and modernized. For a sample of 5,707 once‐married women a path analysis was performed in which age at first marriage was considered a function of age, educational attainment, urban origin, premarital labor‐force participation, and age at menarche. Age at menarche, with a positive effect on the dependent variable, was the most important direct cause of age at first marriage. Although exogenous variables associated with modernization (urban origin, educational attainment and younger age) had a positive direct effect on age at first marriage, they also had a negative indirect effect on age at first marriage through their negative direct effect on age at menarche.     

Assessing the Independent Contribution of Maternal Educational Expectations to Children’s Educational Attainment in Early Adulthood: A Propensity Score Matching Analysis

Background

Parental educational expectations have been associated with children’s educational attainment in a number of long-term longitudinal studies, but whether this relationship is causal has long been debated. The aims of this prospective study were twofold: 1) test whether low maternal educational expectations contributed to failure to graduate from high school; and 2) compare the results obtained using different strategies for accounting for confounding variables (i.e. multivariate regression and propensity score matching).

Methodology/Principal Findings

The study sample included 1,279 participants from the Quebec Longitudinal Study of Kindergarten Children. Maternal educational expectations were assessed when the participants were aged 12 years. High school graduation – measuring educational attainment – was determined through the Quebec Ministry of Education when the participants were aged 22–23 years. Findings show that when using the most common statistical approach (i.e. multivariate regressions to adjust for a restricted set of potential confounders) the contribution of low maternal educational expectations to failure to graduate from high school was statistically significant. However, when using propensity score matching, the contribution of maternal expectations was reduced and remained statistically significant only for males.

Conclusions/Significance

The results of this study are consistent with the possibility that the contribution of parental expectations to educational attainment is overestimated in the available literature. This may be explained by the use of a restricted range of potential confounding variables as well as the dearth of studies using appropriate statistical techniques and study designs in order to minimize confounding. Each of these techniques and designs, including propensity score matching, has its strengths and limitations: A more comprehensive understanding of the causal role of parental expectations will stem from a convergence of findings from studies using different techniques and designs.     

Estimating the Inbreeding Depression on Cognitive Behavior: A Population Based Study of Child Cohort

BackgroundCognitive ability tests are widely assumed to measure maximal intellectual performance and predictive associations between intelligence quotient (IQ) scores and later mental health problems. Very few epidemiologic studies have been done to demonstrate the relationship between familial inbreeding and modest cognitive impairments in children.ObjectiveWe aimed to estimate the effect of inbreeding on children’s cognitive behavior in comparison with non-inbred children.MethodologyA cohort of 408 children (6 to 15 years of age) was selected from inbred and non-inbred families of five Muslim populations of Jammu region. The Wechsler Intelligence Scales for Children (WISC) was used to measure the verbal IQ (VIQ), performance IQ (PIQ) and full scale IQ (FSIQ). Family pedigrees were drawn to access the family history and children’s inbred status in terms of coefficient of inbreeding (F).ResultsWe found significant decline in child cognitive abilities due to inbreeding and high frequency of mental retardation among offspring from inbred families. The mean differences (95% C.I.) were reported for the VIQ, being −22.00 (−24.82, −19.17), PIQ −26.92 (−29.96, −23.87) and FSIQ −24.47 (−27.35, −21.59) for inbred as compared to non-inbred children (p>0.001). The higher risk of being mentally retarded was found to be more obvious among inbred categories corresponding to the degree of inbreeding and the same accounts least for non-inbred children (p<0.0001). We observed an increase in the difference in mean values for VIQ, PIQ and FSIQ with the increase of inbreeding coefficient and these were found to be statistically significant (p<0.05). The regression analysis showed a fitness decline (depression) for VIQ (R² = 0.436), PIQ (R² = 0.468) and FSIQ (R² = 0.464) with increasing inbreeding coefficients (p<0.01).ConclusionsOur comprehensive assessment provides the evidence for inbreeding depression on cognitive abilities among children.     

Stunting,IQ, and final school attainment in the Cebu Longitudinal Health and Nutrition Survey birth cohort

School attainment is an important aspect of human capital, and a key determinant of long-term health and well-being. Early life deprivation and poor nutritional status are well known predictors of school entry and progression. We examine the persistence of early life influences and subsequent socioeconomic disadvantage (SED) across the multiple school continuation decisions that lead to final school attainment. Using data from a Philippine birth cohort followed for 35 years, we model 6 continuation decisions: Did not complete elementary school, elementary graduate only (completed grade 6), some secondary schooling, high school graduate, some postsecondary schooling, and college graduate, as well as total years of schooling. We estimate the association of school attainment with early life length for age Z-score (LAZ at 2 years of age) and cognitive development (IQ) as well as underlying indicators of SED and other family influences through early adulthood. The analysis sample includes >1900 participants in the Cebu Longitudinal Health and Nutrition Survey. Females completed, on average, one year more schooling than males, and twice as many females as males were college graduates (29.1 vs 15.0 %). LAZ and one standard deviation of IQ were each independently associated with 0.4 more years of attained schooling. A path model demonstrated strong direct associations of SED with years of schooling as well as indirect associations through LAZ and IQ. Sequential logits used to estimate continuing education decisions show persistent associations of early life LAZ and IQ and schooling even after accounting for changing SED of households over the schooling life course. Filipino parents had high but often unmet educational aspirations for their children because of the child’s loss of interest in school and perceived financial barriers. Results further emphasize the importance of early life SED as a key risk factor for suboptimal school attainment.     

Evidence that cognitive deficit in children is associated not only with iron deficiency,but also with blood lead concentration: A preliminary study

ObjectiveTo investigate whether blood lead concentrations are elevated in iron-deficient children, and to examine the association between iron deficiency and/or elevated blood lead concentration and cognitive deficits in children.MethodThe present study is a component of the Mothers’ and Children's Environmental Health (MOCEH) study, a multi-center birth cohort project in Korea that began in 2006. The study cohort consisted of 194 children who underwent testing of blood lead and serum C-reactive proteins (CRPs) and ferritin concentrations, and the Korean version of the Wechsler Preschool and Primary Scale of Intelligence, revised edition (WPPSI-R), at 60 months of age. In addition, the mothers’ blood lead concentrations during pregnancy were included in the analyses. Multivariate linear regression analysis was performed to analyze the correlation between high blood lead and low serum ferritin concentrations, after adjustment for covariates, in children, as well as to analyze the association of verbal IQ with serum ferritin and blood lead concentrations.ResultsLead and ferritin concentrations were inversely and significantly associated in children after adjustment for covariates. Moreover, both concentrations were associated with verbal IQ, after adjustment for covariates, and each was associated with cognitive deficits after adjustment for the other. Sobel test statistics showed that blood lead concentration was a significant partial mediator for the relationship between iron deficiency and verbal IQ.ConclusionDue to the results discussed in the present study, cognitive deficit in children seems to be associated not only with iron deficiency, but also with blood lead concentration.     

Ethnicity,sibling, and family correlates of young adults’ status attainment: A follow‐up study

Abstract

Longitudinal data were used to examine relationships among sibling variables, perceptions of family environments, and measures of educational attainment, occupational status, and occupational aspirations. The analyses involved 21‐year‐old Australians from Anglo‐Australian, Greek, and Southern Italian families. Regression surfaces were plotted from models that included terms to test for possible linear, interaction, and curvilinear associations among the variables. The study indicated that sibsize and birth order continued to have many significant associations with young adults’ status attainment even after taking into account the mediating influence of perceived family environments. Also, the investigation suggested that there are ethnic‐group differences in relations among sibling variables, perceived parents’ support for learning, and young adults’ status attainment.     

A natural fiber complex reduces body weight in the overweight and obese: A double‐blind,randomized, placebo‐controlled study

Objective:

A proprietary natural fiber complex (Litramine IQP G‐002AS) derived from Opuntia ficus‐indica, and standardized on lipophilic activity, was previously shown in preclinical and human studies to reduce dietary fat absorption through gastrointestinal (GI) fat binding. Here, we investigated the efficacy and safety of IQP G‐002AS in body weight reduction.

Design and Methods:

One hundred twenty‐five overweight and obese adults participated in the study. Subjects were advised on physical activity, and received nutritional counseling, including hypocaloric diet plans (30% energy from fat and 500 kcal deficit/day). After a 2‐week placebo run‐in phase, subjects were randomized to receive either 3 g/day of IQP G‐002AS (IQ) or a placebo. The primary endpoint was change in body weight from baseline; secondary endpoints included additional obesity measures and safety parameters.

Results:

One hundred twenty‐three subjects completed the 12‐week treatment phase (intention‐to‐treat (ITT) population: 30 male and 93 female; mean BMI: 29.6 ± 2.8 kg/m² and age: 45.4 ± 11.3 years). The mean body weight change from baseline was 3.8 ± 1.8 kg in IQ vs. 1.4 ± 2.6 kg in placebo (P < 0.001). More IQ subjects lost at least 5% of their initial body weight compared to placebo (P = 0.027). Compared with placebo, IQ also showed significantly greater reduction in BMI, body fat composition, and waist circumference. IQ was well tolerated with no adverse reactions reported.

Conclusions:

These results suggest that the natural fiber complex Litramine IQP G‐002AS is effective in promoting weight loss.     

Which Metric of Relative Weight Best Captures Body Fatness in Children?

Objective: To evaluate the relative merits of BMI (kilograms per meter squared) and age‐ and gender‐adjusted BMI, age‐ and gender‐specific z score of BMI, and age‐ and gender‐specific percentiles of BMI as surrogate measures of body fatness among a sample of youth. Research Methods and Procedures: The sample comprised 596 children and adolescents 5 to 18.7 years old and was 40% male and 55% white. Height and weight were measured by trained research staff. DXA was used to determine body fat mass. BMI, age‐ and gender‐specific percentile of BMI, and age‐ and gender‐specific z scores of BMI were computed, and these metrics were compared with measured body fatness. Results: The BMI values in the sample ranged from 12.9 to 55.0 kg/m², with a mean of 24.9 kg/m². The Spearman correlations with percentage body fat were similar for all of the BMI metrics (r = 0.82 to 0.88). Linear regression models with age‐ and gender‐specific percentiles of BMI explained significantly less of the variance (65%) than models with log‐transformed BMI (81%) or age‐ and gender‐specific z scores of BMI (75% to 79%). z scores were the most accurate at classifying children who were overfat (sensitivity = 0.84, specificity = 0.96 for z score ≥1). However, using a BMI ≥85th percentile or a BMI ≥20 kg/m² was also accurate at classifying youth. Discussion: The BMI metrics had similar correlations with body fatness, but age‐ and gender‐specific percentiles of BMI were the least accurate proxy measure of body fatness. However, a BMI z score ≥1, BMI percentile ≥85, and BMI ≥20 kg/m² are all useful for identifying children who may be overfat.     

Further investigations of educational and occupational attainment in the Hawaii family study of cognition

Abstract

Associations of measures of grandparental status, parental status, cognitive abilities, and personality, and own cognitive abilities and personality with educational and occupational attainment are reported for 249 offspring, now 25 years or older, from the Hawaii Family Study of Cognition (HFSC). In general, across two ethnic groups (Americans of European ancestry (AEA) and Americans of Japanese ancestry (AJA)), the data suggest that family background had a relatively trivial influence, own cognitive abilities (particularly verbal ability and general intelligence) substantial influence, and own personality some influence on the educational and occupational attainment of males, while family background had a far more substantial influence than own ability on the attainment of females. Educational attainment was generally found to be substantially predictive of occupational attainment. Hierarchal multiple regression analyses were conducted to assess the influence of parents’ abilities over and above grandparental status and the influence of offsprings’ abilities over and above parental status and abilities on their respective educational and occupational attainments. These analyses also indicated that family background was a much greater influence than own ability on the attainment of AEA female parents and both AEA and AJA female offspring. These findings for female offspring were further confirmed by analyses of parent‐offspring and within‐sibship differences in attainment.     

Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study

ObjectiveTo examine the relation between birth weight and measured intelligence at age 7 years in children within the normal range of birth weight and in siblings.DesignCohort study of siblings of the same sex.Setting12 cities in the United States.Subjects3484 children of 1683 mothers in a birth cohort study during the years 1959 through 1966. The sample was restricted to children born at ⩾37 weeks gestation and with birth weights of 1500-3999 g.ResultsMean IQ increased monotonically with birth weight in both sexes across the range of birth weight in a linear regression analysis of one randomly selected sibling per family (n= 1683) with adjustment for maternal age, race, education, socioeconomic status, and birth order. Within same sex sibling pairs, differences in birth weight were directly associated with differences in IQ in boys (812 pairs, predicted IQ difference per 100 g change in birth weight =0.50, 95% confidence interval 0.28 to 0.71) but not girls (871 pairs, 0.10, −0.09 to 0.30). The effect in boys remained after differences in birth order, maternal smoking, and head circumference were adjusted for and in an analysis restricted to children with birth weight ⩾ 2500 g.ConclusionThe increase in childhood IQ with birth weight continues well into the normal birth weight range. For boys this relation holds within same sex sibships and therefore cannot be explained by confounding from family social environment.

What is already known on this topic

IQ at school age is linked to birth weight among low birthweight babiesSome evidence suggests the association might also apply to children of normal birth weight

What this study adds

IQ at age 7 years is linearly related to birth weight among children of normal birth weightThe relation was not due to confounding by maternal or socioeconomic factorsIQ is also associated with differences in birth weight between boy sibling pairs but not girls     

Psoriatic and psoriatic arthritis patients with and without jet-lag: does it matter for disease severity scores? Insights and implications from a pilot,prospective study

ABSTRACT

Background: Jet-lag may affect air-travelers crossing at least two time-zones and has several health-care implications. It occurs when the human biological rhythms are out of synch with respect to the day-night cycle at the country destination. Its effect in psoriasis is missing. We aimed to evaluate the effect of Jet-lag in psoriatic patients’ management. Methods: This is a prospective observational study that enrolled psoriatic patients that underwent a flight: patients who experienced jet-lag were compared to patients who did not experience jet-lag. Before the flight, a dermatologist recorded clinical and demographical data with particular attention to Psoriasis Area Severity Index (PASI) and Disease Activity in Psoriatic Arthritis (DAPSA). Patients performed Self-Administered Psoriasis Area Severity Index (SAPASI), the Dermatology Life Quality Index (DLQI) and the pruritus Visual Analog Scale (VAS) scores. After the flight, patients completed the SAPASI, DLQI and pruritus-VAS scores. Results: The sample recruited comprised of 70 psoriatic patients aged 42.4 ± 9.7 years (median 42.5 years). Thirty (42.9%) were males, mean BMI was 25.5 ± 2.2 kg/m². Average disease duration was 15.2 ± 7.1 years, and 20 (28.6%) subjects had developed PsA. Average hours of flight were 5.4 ± 3.5 (median 3.5 h), with 34 (48.6%) subjects reporting jet-lag. At the multivariate regression analysis, the change in the SAPASI score resulted correlated with jet-lag (regression coefficient 1.63, p = .0092), as well the change in the DLQI score (regression coefficient = 1.73, p = .0009), but no change on the pruritus VAS scale was found. Conclusions: The present study suggests that jet-lag may influence disease severity and DLQI scores, but not itch in psoriatic patients.     

Intelligence and family size: A paradox resolved

Abstract

IQ data was studied for over a thousand families for both parents and offspring, and also for the non‐reproducing siblings of parents. The inclusion of these siblings allowed the authors to resolve the paradox presented by the failure of the general intelligence level to decline in accord with the large negative correlation (‐0.30) between intelligence and number of children in the family. When the non‐reproducing siblings of the parents are included, the negative correlation disappears. The higher reproductive rate of individuals in the lower IQ groups who are parents is offset by the larger proportion of their siblings who never marry or who fail to reproduce when married. Thus, the IQ level of the whole population should remain relatively static from one generation to the next, or at least not drop rapidly.     

Number of siblings,family background,and the process of educational attainment

Abstract

Sociological research has found that educational attainment is the most important known determinant of men's occupational positions. Since the educational process occurs primarily while boys depend on their families, sociologists are increasingly interested in familial influences on education. This paper concentrates on the number of siblings in the family, and addresses two principal questions concerning the relation of sibship sire to educational outcomes. First, controlling for family background characteristics, does sibship size affect men's educational attainment and, if so, where in the educational process is this effect most evident? Second, among family variables, what is the relative importance of sibship size compared to the father's education, the father's socioeconomic status, farm background, and a broken family? Research was based on probability samples of 57,000 white men in the United States.