Cohort Size and Youth Earnings: Evidence from a Quasi-Experiment

In this paper, I use data from the Canadian Labour Force Surveys (LFS), and the 2001 and 2006 Canadian Censuses to estimate the impact of an important labor supply shock on the earnings of young high-school graduates. The abolition of Ontario’s Grade 13 generated a ‘double’ cohort of high-school graduates that simultaneously entered the Ontario labor market, generating a large and sudden increase in the labor supply. This provides a rare occasion to measure the impact of cohort size on earnings without the supply shock being possibly confounded with unobserved trends—a recurring problem in the literature. The Census findings suggest that the effect of the supply shock is statistically and economically important, depressing weekly earnings by 5 to 9 percent. The findings from Census are supported by the LFS results which suggest that the immediate impact of the supply shock—measured about six months after high-school graduation—is also important.Labor Supply Shock, Youth

Estimating the BenefiÂ…t of High School for College-Bound Students

Studies based on instrumental variable techniques suggest that the value of a high school education is large for potential dropouts, yet we know much less about the size of the benefi…t for students who will go on to post-secondary education. To help …fill this gap, I measure the value-added of a year of high-school mathematics for university-bound students using a recent Ontario secondary school reform. The subject speci…ficity of this reform makes it possible to identify the benefi…t of an extra year of mathematics despite the presence of self-selection: one can use subjects unaffected by the reform to control for potential ability differences between control and treatment groups. Further, the richness of the data allows me to generalize the standard difference-in-differences estimator, correcting for heterogeneity in ability measurement across subjects. The estimated value- added to an extra year of mathematics is small for these students –of the order of 17 percent of a standard deviation in university grades. This evidence helps to explain why the literature fi…nds only modest effects of taking more mathematics in high school on wages, the small monetary gain being due to a lack of subject-speci…c human capital accumulation. Within- and between-sample comparisons also suggest that the extra year of mathematics benefi…ts lower-ability students more than higher-ability students.Human Capital, High School Curriculum, Education Reform, Mathematics, Factor Model

Union Membership and Perceived Job Insecurity: 30 Years of Evidence from the American General social Survey

Using the Amercian General Social Survey, we explore the link between union membership and perceived job insecurity. This finding is mainly atributed to the primary and secondary sectors and for recessionary periods. Instrumental-variables estimation and the use of attitudinal proxy variables suggest that the positive correlation union membership and perceived job insecurity is not due to self-selection.Union, Perceived Job Insecurity

Estimating the Benefit of High School for College-Bound Students

Studies based on instrumental variable techniques suggest that the value of a high school education is large for potential dropouts, yet we know much less about the size of the benefit for students who will go on to post-secondary education. To help fill this gap, I measure the value-added of a year of high-school mathematics for university-bound students using a recent Ontario secondary school reform. The subject specificity of this reform makes it possible to identify the benefit of an extra year of mathematics despite the presence of self-selection: one can use subjects unaffected by the reform to control for potential ability differences between control and treatment groups. Further, the richness of the data allows me to generalize the standard difference-in-differences estimator, correcting for heterogeneity in ability measurement across subjects. The estimated value-added to an extra year of mathematics is small for these students – of the order of 17 percent of a standard deviation in university grades. This evidence helps to explain why the literature finds only modest effects of taking more mathematics in high school on wages, the small monetary gain being due to a lack of subject-specific human capital accumulation. Within- and between-sample comparisons also suggest that the extra year of mathematics benefits lowerability students more than higher-ability students.Human Capital, High School Curriculum, Education Reform, Mathematics, Factor Model

The ‘Trendiness’ of Sleep: An Empirical Investigation into the Cyclical Nature of Sleep Time

Using Canadian time use data, we exploit exogenous variation in local unemployment rates to investigate the cyclical nature of sleep time and show that for both men and women, sleep time decreases when the economy is doing relatively better. Our results suggest that in a recession Canadians sleep an average of 2 hours and 34 minutes more per week, or 22 minutes more per day. Given the importance of even small changes in sleep time on measures of cognitive functioning such as reaction time and concentration, our findings may help explain the countercyclical nature of mortality. Further, as we find that sleep is affected by the same economic variables (notably the unemployment rate) that affect market work time, our results also contribute to the limited literature that shows that sleep time should not be treated as exogenously determined, but, like any other resource, determined by its relative cost.Business Cycles, Sleep.

The ‘Trendiness’ of Sleep: An Empirical Investigation into the Cyclical Nature of Sleep Time

Using Canadian time use data, we exploit exogenous variation in local unemployment rates to investigate the cyclical nature of sleep time and show that for both men and women, sleep time decreases when the economy is doing relatively better. Our results suggest that in a recession Canadians sleep an average of 2 hours and 34 minutes more per week, or 22 minutes more per day. Given the importance of even small changes in sleep time on measures of cognitive functioning such as reaction time and concentration, our findings may help explain the countercyclical nature of mortality. Further, as we find that sleep is affected by the same economic variables (notably the unemployment rate) that affect market work time, our results also contribute to the limited literature that shows that sleep time should not be treated as exogenously determined, but, like any other resource, determined by its relative cost. Pierre Brochu is an Assistant Professor in the Department of Economics at the University of Ottawa. He received his B.A. and M.A. from the University of Toronto and his Ph.D. from the University of British Columbia. His research interests include labour economics, applied health economics and applied econometrics. His research has mainly focused on the employee-employer relationship; more specifically, job security and job stability

Combining omics data to identify genes associated with allergic rhinitis

Allergic rhinitis is a common chronic disorder characterized by immunoglobulin E-mediated inflammation. To identify new genes associated with this trait, we performed genome- and epigenome-wide association studies and linked marginally significant CpGs located in genes or its promoter and SNPs located 1 Mb from the CpGs, by identifying cis methylation quantitative trait loci (mQTL). This approach relies on functional cellular aspects rather than stringent statistical correction. We were able to identify one gene with significant cis-mQTL for allergic rhinitis, caudal-type homeobox 1 (CDX1). We also identified 11 genes with marginally significant cis-mQTLs (p < 0.05) including one with both allergic rhinitis with or without asthma (RNF39). Moreover, most SNPs identified were not located closest to the gene they were linked to through cis-mQTLs counting the one linked to CDX1 located in a gene previously associated with asthma and atopic dermatitis. By combining omics data, we were able to identify new genes associated with allergic rhinitis and better assess the genes linked to associated SNPs

Longitudinal follow-up of the asthma status in a French–Canadian cohort

Asthma affects 340 million people worldwide and varies in time. Twenty years ago, in Canada, the Saguenay–Lac-Saint-Jean asthma family cohort was created to study the genetic and environmental components of asthma. This study is a follow-up of 125 participants of this cohort to explore the appearance, persistence, and progression of asthma over 10–20 years. Participants answered a clinical standardized questionnaire. Lung function was assessed (forced expiratory volume in 1 s, forced vital capacity, bronchial reversibility, and methacholine bronchoprovocation), skin allergy testing was performed, blood samples were obtained (immunoglobulin E, white blood cell counts) and phenotypes were compared between recruitment and follow-up. From the participants without asthma at recruitment, 12% developed a phenotype of adult-onset asthma with the presence of risk factors, such as atopy, high body mass index, and exposure to smoking. A decrease of PC20 values in this group was observed and a decrease in the FEV1/FVC ratio in all groups. Also, 7% of individuals with asthma at recruitment developed chronic obstructive pulmonary disease, presenting risk factors at recruitment, such as moderate-to-severe bronchial hyperresponsiveness, exposure to smoking, and asthma. This study allowed a better interpretation of the evolution of asthma. Fine phenotypic characterization is the first step for meaningful genetic and epigenetic studies

How Tightly Linked Are Pericopsis elata (Fabaceae) Patches to Anthropogenic Disturbances in Southeastern Cameroon?

peer reviewedWhile most past studies have emphasized the relationships between specific forest stands and edaphic factors, recent observations in Central African moist forests suggested that an increase of slash-and-burn agriculture since 3000–2000 BP (Before Present) could be the main driver of the persistence of light-demanding tree species. In order to examine anthropogenic factors in the persistence of such populations, our study focused on Pericopsis elata, an endangered clustered timber species. We used a multidisciplinary approach comprised of botanical, anthracological and archaeobotanical investigations to compare P. elata patches with surrounding stands of mixed forest vegetation (“out-zones”). Charcoal samples were found in both zones, but were significantly more abundant in the soils of patches. Eleven groups of taxa were identified from the charcoals, most of them also present in the current vegetation. Potsherds were detected only inside P. elata patches and at different soil depths, suggesting a long human presence from at least 2150 to 195 BP, as revealed by our charcoal radiocarbon dating. We conclude that current P. elata patches most likely result from shifting cultivation that occurred ca. two centuries ago. The implications of our findings for the dynamics and management of light-demanding tree species are discussed