Showing papers by "Roy Thurik published in 2016"
TL;DR: In this article, the results of a genome-wide association study (GWAS) for educational attainment were reported, showing that single-nucleotide polymorphisms associated with educational attainment disproportionately occur in genomic regions regulating gene expression in the fetal brain.
Abstract: Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our earlier discovery sample of 101,069 individuals to 293,723 individuals, and a replication study in an independent sample of 111,349 individuals from the UK Biobank. We identify 74 genome-wide significant loci associated with the number of years of schooling completed. Single-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural development. Our findings demonstrate that, even for a behavioural phenotype that is mostly environmentally determined, a well-powered GWAS identifies replicable associated genetic variants that suggest biologically relevant pathways. Because educational attainment is measured in large numbers of individuals, it will continue to be useful as a proxy phenotype in efforts to characterize the genetic influences of related phenotypes, including cognition and neuropsychiatric diseases.
1,102 citations
17 Jun 2016
975 citations
Aysu Okbay1, Bart M. L. Baselmans2, Jan-Emmanuel De Neve3, Patrick Turley4 +213 more•Institutions (65)
TL;DR: In this paper, the authors conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n= 161,460), and neuroticism(n = 170,911).
Abstract: Very few genetic variants have been associated with depression and neuroticism, likely because of limitations on sample size in previous studies. Subjective well-being, a phenotype that is genetically correlated with both of these traits, has not yet been studied with genome-wide data. We conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n = 161,460), and neuroticism (n = 170,911). We identify 3 variants associated with subjective well-being, 2 variants associated with depressive symptoms, and 11 variants associated with neuroticism, including 2 inversion polymorphisms. The two loci associated with depressive symptoms replicate in an independent depression sample. Joint analyses that exploit the high genetic correlations between the phenotypes (|ρ^| ≈ 0.8) strengthen the overall credibility of the findings and allow us to identify additional variants. Across our phenotypes, loci regulating expression in central nervous system and adrenal or pancreas tissues are strongly enriched for association.
796 citations
17 Jun 2016
392 citations
TL;DR: In this paper, the authors analyzed the differences between business owners motivated by opportunity and necessity in terms of their socioeconomic characteristics, personality, and perceptions of entrepreneurial support, and found that those who prefer being a business owner and those who have more favorable perceptions of financial start-up support are more likely to be an opportunity versus a necessity business owner.
Abstract: The scholarly literature often distinguishes between so-called opportunity and necessity entrepreneurship and between “pull” and “push” motivations. Despite the pervasive use of this terminology, empirical analyses are mostly based on a single country. The present paper contributes by investigating business owner survey data for the United States and 32 countries in Europe and Asia. We analyze the differences between business owners motivated by opportunity and necessity in terms of their (1) socioeconomic characteristics, (2) personality, and (3) perceptions of entrepreneurial support. Descriptive statistics reveal that the two groups of business owners have very different profiles along these three dimensions. Moreover, multinomial logit regressions indicate that the determinants of business ownership (versus paid employment) differ for opportunity and necessity business ownership. A specific result of the present study (covering all 33 countries) is that the probability of being an opportunity versus a necessity business owner is higher for male, younger, wealthier, proactive, and optimistic business owners. Furthermore, those who prefer being a business owner and those who have more favorable perceptions of financial start-up support are more likely to be an opportunity versus a necessity business owner.
275 citations
TL;DR: In this article, the authors reported a large genome-wide association study of both sexes including 251,151 individuals for AB and 343,072 individuals for NEB and identified 12 independent loci that are significantly associated with AB and NEB.
Abstract: The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits
237 citations
22 Dec 2016
176 citations
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TL;DR: In this paper, the authors conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n= 161,460), and neuroticism(n = 170,911).
Abstract: Very few genetic variants have been associated with depression and neuroticism, likely because of limitations on sample size in previous studies. Subjective well-being, a phenotype that is genetically correlated with both of these traits, has not yet been studied with genome-wide data. We conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n = 161,460), and neuroticism (n = 170,911). We identify 3 variants associated with subjective well-being, 2 variants associated with depressive symptoms, and 11 variants associated with neuroticism, including 2 inversion polymorphisms. The two loci associated with depressive symptoms replicate in an independent depression sample. Joint analyses that exploit the high genetic correlations between the phenotypes (\textbarρ^\textbar ? 0.8) strengthen the overall credibility of the findings and allow us to identify additional variants. Across our phenotypes, loci regulating expression in central nervous system and adrenal or pancreas tissues are strongly enriched for association.
132 citations
TL;DR: The results show that certain aspects of ADHD, in particular hyperactivity, can have a bright side, as they are positively associated with self-employment, according to a population-based sample from the STAGE cohort of the Swedish Twin Registry.
Abstract: Attention-deficit/hyperactivity (ADHD) symptoms have been associated with the decision to become self-employed. Although these symptoms are generally regarded as disadvantageous, there may also be a bright side. To our knowledge, however, there has been no systematic, epidemiological evidence to support this claim. This paper examines the association between ADHD symptoms and self-employment in a population-based sample from the STAGE cohort of the Swedish Twin Registry (N = 7208). For replication, we used a sample of Dutch students who participated in the Global University Entrepreneurial Spirit Students’ Survey (N = 13,112). In the Swedish sample, we found a positive association with self-employment for both general ADHD symptoms [odds ratio (OR) 1.13; 95 % confidence intervals (CI) 1.04–1.23] and hyperactivity symptoms [OR 1.19; 95 % CI 1.08–1.32], whereas no association was found for attention-deficit symptoms [OR 0.99; 95 % CI 0.89–1.10]. The positive association between hyperactivity and self-employment was replicated in the Dutch student sample [OR 1.09; 95 % CI 1.03–1.15]. Our results show that certain aspects of ADHD, in particular hyperactivity, can have a bright side, as they are positively associated with self-employment.
62 citations
TL;DR: In this paper, the authors investigated the link between ADHD symptoms and entrepreneurial orientation (EO) and found that ADHD symptoms have helped entrepreneurs in their careers and contributed to their understanding of entrepreneurship, particularly the determinants of EO.
Abstract: This study investigates the link between attention deficit hyperactivity disorder (ADHD) symptoms and entrepreneurial orientation (EO). EO is known to be a crucial factor for small firm survival and growth, conceptualised as a business characteristic but influenced by the personality of the small business owner and measured at her individual level. There is ample anecdotal evidence claiming that ADHD symptoms have helped entrepreneurs in their careers. Using a data set of French small firm owners, we are the first to go beyond the anecdotal level in linking ADHD symptoms and EO. Our study contributes to our understanding of entrepreneurship, particularly the determinants of EO, and to “destigmatising” ADHD, which is considered solely a clinical disorder that should be treated.
55 citations
01 Oct 2016
TL;DR: A large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB finds 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome- wide association study and 4 additional loci associated in a gene-based effort.
Abstract: The genetic architecture of human reproductive behavior—age at first birth (AFB) and number of children ever born (NEB)—has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits.
TL;DR: In this paper, the authors analyze whether entrepreneur location decisions differ across industries and identify the factors determining the choice of location between rural and urban environments, based on a new taxonomy developed over the influential three dimensions of Hayter's (1997) approach.
Abstract: In this paper we analyse whether entrepreneur location decisions differ across industries and identify the factors determining the choice of location between rural and urban environments. Firm location is based on a new taxonomy developed over the influential three dimensions of Hayter’s (1997) approach. The paper uses data from sample of one thousand Portuguese firms. We present a stylized theoretical model to determine how these new five dimensions influence firm’s location and test the model through a logistic regression. Our results show that that the location decisions depend on the sector of activity, type of area (urban vs. rural) and the characteristics of the entrepreneur. We find that companies engaged in knowledge intensive business services prefer to locate in urban areas. From an institutional point of view, firms prefer to locate in rural areas.
TL;DR: The authors' results show the importance of including inertia when studying customers' continuance intention and taking into account the specific moderating effect of contractual subscription.
Abstract: Using a status quo bias perspective, this paper examines the relation between customers' inertia and continuance intention, identifying the moderating role of contractual subscription on this relationship The authors' model is validated using data collected from 457 mobile phone service customers and partial least squares Results show that customers continue with mobile service providers due to their inertia resulting from habit and switching costs The effect of customers' inertia on their continuance intention is stronger when they have a contractual subscription with the mobile service provider The authors' results show the importance of including inertia when studying customers' continuance intention and taking into account the specific moderating effect of contractual subscription
01 Jan 2016
TL;DR: In this paper, the authors investigate the nature of the competition process in retailing by contrasting blue ocean strategy and competitive strategy and develop a methodology to test the core assumptions of both these major schools of strategic management.
Abstract: We investigate the nature of the competition process in retailing by contrasting blue ocean strategy and competitive strategy. We develop a methodology to test the core assumptions of both these major schools of strategic management. Applying this methodology to a large data set of shop type averages within the retailing sector, we find empirical support for blue ocean strategy in terms of creating new retail market space. At the same time we also find support for competitive forces eroding temporary profits. However, we find that these forces are sufficiently slow to enable periods of supernormal profits for retail innovators.
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TL;DR: This paper investigated how the type of work experience gained from prior paid employment influences the path to entrepreneurship and distinguish between two distinct entrepreneurship entry modes: business takeover and new venture start-up.
Abstract: Our paper investigates how the type of work experience gained from prior paid employment influences the path to entrepreneurship. We distinguish between two distinct entrepreneurship entry modes: business takeover and new venture start-up. Using a large and rich French data set, we find that small firm experience increases the likelihood for business takeover, whereas management and same sector experience both increase the likelihood for new ventures. Our findings are relevant for policymakers aiming to improve the business transfer process.
TL;DR: The online Meta-GWAS Accuracy and Power calculator is described which quantifies this attenuation based on a novel multi-study framework and shows that imperfect genetic correlations between studies substantially decrease statistical power and predictive accuracy and, thereby, contribute to the missing heritability.
Abstract: Large-scale genome-wide association results are typically obtained from a fixed-effects meta-analysis of GWAS summary statistics from multiple studies spanning different regions and/or time periods. This approach averages the estimated effects of genetic variants across studies. In case genetic effects are heterogeneous across studies, the statistical power of a GWAS and the predictive accuracy of polygenic scores are attenuated, contributing to the so-called 'missing heritability'. Here, we describe the online Meta-GWAS Accuracy and Power calculator (MetaGAP; available at www.devlaming.eu) which quantifies this attenuation based on a novel multi-study framework. By means of simulation studies, we show that under a wide range of genetic architectures, the statistical power and predictive accuracy provided by this calculator are accurate. We compare the predictions from MetaGAP with actual results obtained in the GWAS literature. Specifically, we use genomic-relatedness-matrix restricted maximum likelihood (GREML) to estimate the SNP heritability and cross-study genetic correlation of height, BMI, years of education, and self-rated health in three large samples. These estimates are used as input parameters for the MetaGAP calculator. Results from the calculator suggest that cross-study heterogeneity has led to attenuation of statistical power and predictive accuracy in recent large-scale GWAS efforts on these traits (e.g., for years of education, we estimate a relative loss of 51–62% in the number of genome-wide significant loci and a relative loss in polygenic score R2 of 36–38%). Hence, cross-study heterogeneity contributes to the missing heritability.
TL;DR: In this article, the authors made a technical mistake in Table 3 where the asterisks were placed after the second value (standard errors) instead of after the first value (coefficient).
Abstract: Due to a technical mistake in Table 3 the asterisks were placed after the second value (standard errors) instead of after the first value (coefficient).
In addition there should have been parentheses around the second values (standard errors) in lines.
The publisher apologizes for this mistake. The original article was corrected.
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TL;DR: The authors investigated how the type of work experience gained from prior paid employment influences the path to entrepreneurship and distinguish between two distinct entrepreneurship entry modes: business takeover and new venture start-up.
Abstract: Our paper investigates how the type of work experience gained from prior paid employment influences the path to entrepreneurship. We distinguish between two distinct entrepreneurship entry modes: business takeover and new venture start-up. Using a large and rich French data set, we find that small firm experience increases the likelihood for business takeover, whereas management and same sector experience both increase the likelihood for new ventures. Our findings are relevant for policymakers aiming to improve the business transfer process.