| 1. |
- Ploederl, Martin, et al.
(författare)
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Daylight saving time was not associated with a change in suicide rates in Austria, Switzerland and Sweden
- 2024
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Ingår i: European Journal of Public Health. - 1101-1262 .- 1464-360X. ; 34:4, s. 717-722
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Tidskriftsartikel (refereegranskat)abstract
- Background: Some studies have reported an increase in suicides after the start of daylight saving time (DST), but the evidence is mixed and more research about proposed mechanisms (disrupted sleep, changing light exposure) is needed. Methods: In our preregistered study, we analyzed change in suicide rates in the 2 weeks before/after DST, based on data between 1980 and 2022 from Austria, Switzerland and Sweden, using Poisson regression models and changepoint analyses. To explore the impact of disrupted sleep, we repeated the analysis for retired people who are likely less bound to DST, and for younger people. To explore the effect of changed daylight exposure, we repeated the analysis for northern and southern regions because twilight and daylight exposure varies by latitude. Results: Suicide rates did not significantly increase after the start of DST (adjusted incidence rate ratio IRR = 0.98, 95% CI 0.91-1.06, P = 0.66, n = 13 362 suicides) or after DST ended (adjusted IRR = 0.99, 95% CI 0.91-1.07, P = 0.76, n = 12 319 suicides). There were no statistically significant findings among younger or older subgroups and also not in Sweden and Austria/Switzerland. No changepoints were detected. Conclusions: There were no significant changes in suicide rates associated with DST and no clear evidence to support proposed mechanisms (light exposure, disruption of sleep). Our study is one of the largest and was adequately powered. Nonetheless, even larger studies to detect smaller effects could be important to inform the debate about harms and benefits of DST.
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| 4. |
- Brown, Nicholas, et al.
(författare)
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Testing Factors in CCE
- 2023
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Ingår i: Economics Letters. - 0165-1765. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- One of the most popular estimators of interactive effects panel data models is the common correlated effects (CCE) approach, which uses the cross-sectional averages of the observables to estimate the unobserved factors. The present paper proposes a simple test statistic that is suitable for testing hypotheses about these factors. The statistic can be used to test if a subset of the averages is enough to estimate the factors, or if there are observable variables that capture them. The statistic can also be used sequentially to determine the smallest set of averages needed to estimate the factors.
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| 5. |
- Hökby, Sebastian, et al.
(författare)
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Longitudinal Effects of Screen Time on Depressive Symptoms among Swedish Adolescents : The Moderating and Mediating Role of Coping Engagement Behavior.
- 2023
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- Studies suggest that hourly digital screen time increases adolescents' depressive symptoms and emotional regulation difficulties. However, causal mechanisms behind such associations remain unclear. We hypothesized that problem-focused and/or emotion-focused engagement coping moderates and possibly mediates this association over time. Questionnaire data were collected in three waves from a representative sample of Swedish adolescents (0, 3 and 12 months; n = 4793; 51% boys; 99% aged 13-15). Generalized Estimating Equations estimated the main effects and moderation effects, and structural regression estimated the mediation pathways. The results showed that problem-focused coping had a main effect on future depression (b = 0.030; p < 0.001) and moderated the effect of screen time (b = 0.009; p < 0.01). The effect size of this moderation was maximum 3.4 BDI-II scores. The mediation results corroborated the finding that future depression was only indirectly correlated with baseline screen time, conditional upon intermittent problem-coping interference (C'-path: Std. beta = 0.001; p = 0.018). The data did not support direct effects, emotion-focused coping effects, or reversed causality. We conclude that hourly screen time can increase depressive symptoms in adolescent populations through interferences with problem-focused coping and other emotional regulation behaviors. Preventive programs could target coping interferences to improve public health. We discuss psychological models of why screen time may interfere with coping, including displacement effects and echo chamber phenomena.
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| 6. |
- Kaddoura, Yousef, et al.
(författare)
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Estimation of Panel Data Models with Random Interactive Effects and Multiple Structural Breaks when T is Fixed
- 2023
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Ingår i: Journal of Business and Economic Statistics. - : Informa UK Limited. - 0735-0015 .- 1537-2707. ; 41:3, s. 778-790
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we propose a new estimator of panel data models with random interactive effects and multiple structural breaks that is suitable when the number of time periods, T, is fixed and only the number of cross-sectional units, N, is large. This is done by viewing the determination of the breaks as a shrinkage problem, and to estimate both the regression coefficients, and the number of breaks and their locations by applying a version of the Lasso approach. We show that with probability approaching one the approach can correctly determine the number of breaks and the dates of these breaks, and that the estimator of the regime-specific regression coefficients is consistent and asymptotically normal. We also provide Monte Carlo results suggesting that the approach performs very well in small samples, and empirical results suggesting that while the coefficients of the controls are breaking, the coefficients of the main deterrence regressors in a model of crime are not.
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| 7. |
- Karavias, Yiannis, et al.
(författare)
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Structural Breaks in Interactive Effects Panels and the Stock Market Reaction to COVID-19
- 2023
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Ingår i: Journal of Business and Economic Statistics. - : Informa UK Limited. - 0735-0015 .- 1537-2707. ; 41:3, s. 653-666
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Tidskriftsartikel (refereegranskat)abstract
- Dealing with structural breaks is an essential step in most empirical economic research. This is particularly true in panel data comprised of many cross-sectional units, which are all affected by major events. The COVID-19 pandemic has affected most sectors of the global economy; however, its impact on stock markets is still unclear. Most markets seem to have recovered while the pandemic is ongoing, suggesting that the relationship between stock returns and COVID-19 has been subject to structural break. It is therefore important to know if a structural break has occurred and, if it has, to infer the date of the break. Motivated by this last observation, the present article develops a new break detection toolbox that is applicable to different sized panels, easy to implement and robust to general forms of unobserved heterogeneity. The toolbox, which is the first of its kind, includes a structural change test, a break date estimator, and a break date confidence interval. Application to a panel covering 61 countries from January 3 to September 25, 2020, leads to the detection of a structural break that is dated to the first week of April. The effect of COVID-19 is negative before the break and zero thereafter, implying that while markets did react, the reaction was short-lived. A possible explanation is the quantitative easing programs announced by central banks all over the world in the second half of March. Supplementary materials for this article are available online.
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| 8. |
- Plöderl, Martin, et al.
(författare)
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Increased suicide risk among younger women in winter during full moon in northern Europe : An artifact or a novel finding?
- 2023
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Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 28, s. 901-907
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Tidskriftsartikel (refereegranskat)abstract
- Available evidence suggests that there is no effect of moon phases on suicidal behavior. However, a Finnish study recently reported elevated suicide rates during full-moon, but only among premenopausal women and only in winter. This could not be replicated in an Austrian study and stirred a discussion about whether the Finnish finding was false-positive or if there are unaccounted moderator variables differing between Finland and Austria. The goal of the present study was to provide another replication with data from Sweden, which is geographically more comparable to Finland than Austria. We also investigated the discussed moderator variables latitude and nightly artificial brightness. There were 48,537 suicides available for analysis. The fraction of suicides during the full-moon quarter in winter did not differ significantly from the expected 25% among premenopausal women (23.3%) and in the full sample (24.7%). The incidence risk ratios for full moon quarter in Poisson regression models were 0.96 (95% CI: 0.90–1.02) for premenopausal women and 1.01 (95% CI: 0.99–1.04) for the full sample. According to Bayes-factor analysis, the evidence supports the null-hypothesis (no association) over the alternative hypothesis (some association). We found similar results when we split the data by latitude and artificial nightly brightness, respectively. In line with the Austrian study, there was no increase of suicides in Sweden among premenopausal women in winter during full-moon. The results from the Finnish study are likely false positive, perhaps resulting from problematic but common research and publication practices, which we discuss.
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| 10. |
- Karabiyik, Hande, et al.
(författare)
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Panel data measures of price discovery
- 2022
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Ingår i: Econometric Reviews. - : Informa UK Limited. - 0747-4938 .- 1532-4168. ; 41:3, s. 269-290
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers disaggregated price data that are observed not only for multiple markets over extended periods of time, but also for a large number of assets. The previous literature has argued that in such data rich environments, which arise frequently in applied work, the analysis of price discovery can be made more precise by accounting for the panel structure of the data. Moreover, since the individual assets are not that interesting anyways, little is lost by taking the overall panel perspective. These arguments are, however, mainly based on empirical observations, and there is little in terms of econometric support. The purpose of the present study is to fill this gap in the literature. This is done by offering a full-blown econometric analysis of panel analogs of the information share and permanent–transitory measures of price discovery, which are the workhorses of the time series literature. Both measures are shown to be consistent and they support standard normal inference, which is in contrast to the time series case, where such inference is only possible for the permanent–transitory measure.
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