Empirical Economics最新文献

This study employs Chilean administrative data to investigate the impact of school starting age on the characteristics of students’ initial enrolled schools. Employing minimum age requirements and an RD design to mitigate endogeneity concerns, we identify benefits linked to commencing school at a later age. Our findings demonstrate that children starting school at an older age enroll in institutions with higher average scores in standardized tests and interact with older peers whose parents have higher education levels. Furthermore, they display a heightened likelihood of entering schools employing academic selection methods, a greater proportion of full-time teachers, and a larger percentage of instructors with a 4-year college degree. The analysis by level of education of the parents and gender reveals that most of our results are driven by parents with lower levels of education and girls. Subgroup analyses further reveal that many of our results are driven by parents with lower levels of education and parents of girls.

This paper studies whether forced increases in the residual working life, determined by a restrictive pension reform, induce additional training activities. By exploiting a sizable Italian pension reform, in a difference-in-differences setting, I find that a lengthening of the working horizon increases, through training, workers’ human capital. Additionally, I show that the response to the reform appears very heterogeneous and depends on gender, age, education, marital status, sector of employment and firm size. My estimates suggest, furthermore, that these individual positive effects are not attributable to employers’ sponsorship.

With mean instrumental variables regression, k-class estimators have the potential to reduce bias, which is larger with weak instruments. With instrumental variables quantile regression, weak instrument-robust estimation is even more important because there is less guidance for assessing instrument strength. Motivated by this, we introduce an analogous k-class of estimators for instrumental variables quantile regression. We show the first-order asymptotic distribution under strong instruments is equivalent for all conventional choices of k. We evaluate finite-sample median bias in simulations for a variety of k, including the k for the conventional k-class estimator corresponding to limited information maximum likelihood (LIML). Computation is fast for all k, and compared to the (k=1) benchmark estimator (analogous to 2SLS), using the LIML k reliably reduces median bias in a variety of data-generating processes, especially when the degree of overidentification is larger. We also revisit some empirical estimates of consumption Euler equations derived from quantile utility maximization. All code is provided online (https://kaplandm.github.io).

Abstract

In this paper, we consider a fractionally integrated multi-level dynamic factor model (FI-ML-DFM) to represent commonalities in the hourly evolution of realized volatilities of several international exchange rates. The FI-ML-DFM assumes common global factors active during the 24 h of the day, accompanied by intermittent factors, which are active at mutually exclusive times. We propose determining the number of global factors using a distance among the intermittent loadings. We show that although the bulk of common dynamics of exchange rates realized volatilities can be attributed to global factors, there are non-negligible effects of intermittent factors. The effect of the COVID-19 on the realized volatility comovements is stronger on the first global-in-time factor, which shows a permanent increase in the level. The effects on the second global factor and on the intermittent factors active when the EU, UK and US markets are operating are transitory lasting for approximately a year after the pandemic starts. Finally, there seems to be no effect of the pandemic neither on the third global factor nor on the intermittent factor active when the markets in Asia are operating.

This paper proposes a nonlinear fractional unit root approach which is known as the autoregressive neural network–fractional integration (ARNN–FI) test. This new fractional integration test is based on a new multilayer perceptron of a neural network process, proposed in Yaya et al. (Oxf Bull Econ Stat 83(4):960–981, 2021). The asymptotic theory and the properties of the proposed test are given. By setting up a Monte Carlo simulation experiment, the simulation results reveal that as the number of observations increases, size and power distortions would disappear in the test. The empirical application based on this new test reveals that the unemployment rates of three European countries are neither stationary nor mean-reverting in line with the hysteresis hypothesis.

Study objectives: In coronary artery bypass grafting (CABG), abnormal cardiac repolarization is associated with adverse cardiovascular events that can be measured via the QTc interval. We investigated the impact of obstructive sleep apnea on the change in repolarization after CABG and the association of change in repolarization with the occurrence of major adverse cardiac and cerebrovascular events.

Methods: A total of 1,007 patients from 4 hospitals underwent an overnight sleep study prior to a nonemergent CABG. Electrocardiograms of 954 patients (median age: 62 years; male: 86%; mean follow-up: 2.1 years) were acquired prospectively within 48 hours before CABG (T1) and within 24 hours after CABG (T2). QTc intervals were measured using the BRAVO algorithm by Analyzing Medical Parameters for Solutions LLC. The change in T2 from T1 for QTc (ΔQTc) was derived, and Cox regression was performed.

Results: Compared with those without, patients who developed major adverse cardiac and cerebrovascular events (n = 115) were older and had (1) a higher prevalence of smoking, hypertension, diabetes mellitus, and chronic kidney disease; (2) a higher apnea-hypopnea index and oxygen desaturation index; and (3) a smaller ΔQTc. Cox regression analysis demonstrated a smaller ΔQTc to be an independent risk factor for major adverse cardiac and cerebrovascular events (hazard ratio: 0.997; P = .032). In the multivariable regression model, a higher oxygen desaturation index was independently associated with a smaller ΔQTc (correlation coefficient: -0.58; P < .001).

Conclusions: A higher preoperative oxygen desaturation index was an independent predictor of a smaller ΔQTc. ΔQTc within 24 hours after CABG could be a novel predictor of occurrence of major adverse cardiac and cerebrovascular events at medium-term follow-up.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: Undiagnosed Sleep Apnea and Bypass OperaTion (SABOT); URL: https://classic.clinicaltrials.gov/ct2/show/NCT02701504; Identifier: NCT02701504.

Citation: Teo YH, Yong CL, Ou YH, et al. Obstructive sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting. J Clin Sleep Med. 2024;20(1):49-55.

Abstract

We analyze diverse and heterogeneous literature to grasp the general effect size of financial development on economic growth on a world scale. For that, we perform by far the largest available meta-analysis of the finance–growth nexus using 3561 estimates collected from 177 studies. Our meta-synthesis results show that large heterogeneity in empirical evidence is, in fact, driven by only a limited number of variables (moderators). By using advanced techniques, we also document the existence of the publication selection bias that is propagated in the literature in a nonlinear fashion. We account for uncertainty in moderator selection by employing model-averaging techniques. After adjusting for the publication bias, the results of our meta-regression provide evidence of a small but genuine positive effect of the financial development on growth that very mildly declines over time. Finance channeled via capital markets seems to be more beneficial for economic growth than that provided in the form of private credit. Our evidence goes against arguments about the damaging role of financial development and is in line with century-old theoretical foundations that favor the positive role of finance on economic growth.