Fixed-effects Model Research Articles

Association Between Ambient Air Pollution and Attention-Deficit/Hyperactivity Disorder (ADHD) in Children: A Systematic Review and Meta-Analysis.

The objective of this systematic review and meta-analysis was to assess the association between postnatal exposure to ambient air pollutants (particulate matter (PM)2.5, PM10, nitrogen dioxide (NO2)) and the risk of attention-deficit/hyperactivity disorder (ADHD) in children. Observational studies, including cohort, case-control, and cross-sectional designs, that examined the relationship between postnatal exposure to ambient air pollution and ADHD in children were included, while studies focusing on prenatal exposure or unrelated neurodevelopmental outcomes were excluded. A comprehensive search of databases including PubMed, Web of Science, Embase, and Ovid, last updated in May 2024, was conducted. The risk of bias in the selected studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools, with discrepancies resolved through discussion among four reviewers. A meta-analysis was performed, synthesizing results using hazard ratios (HR), odds ratios (OR), and risk ratios (RR) as effect sizes. Random effects models were applied in most analyses due to the expected variability between studies, while fixed effects models were employed where only two studies were available. A total of 25 studies were included, with sample sizes ranging from 174 to 35,103 children. The studies were conducted in different countries and varied in their design and pollutant exposure measurement methods. The meta-analysis demonstrated a significant association between PM2.5 exposure and ADHD, with moderate heterogeneity (I² = 74.2%). PM10 exposure was also significantly associated with ADHD, and the heterogeneity was reduced to 34.94% after excluding an influential outlier. NO2 exposure similarly showed a significant association with ADHD, with low heterogeneity (I² = 0%). Due to the limited number of studies per pollutant (ranging from two to six), publication bias was not assessed. Despite the significant findings, there were limitations, including moderate to high heterogeneity among studies and the small number of studies per pollutant, which restricted the ability to assess publication bias and impacted the robustness of the results. Differences in exposure measurement methods and study designs also contributed to variability in the findings. Nonetheless, the evidence suggests that postnatal exposure to ambient air pollutants, particularly PM2.5, PM10, and NO2, is significantly associated with an increased risk of ADHD in children. These results underscore the importance of conducting further large-scale, high-quality studies to explore these associations in greater depth and to elucidate the mechanisms underlying the link between air pollution and ADHD.

Complications of tunneled and non-tunneled peripherally inserted central catheter placement in chemotherapy-treated cancer patients: a meta-analysis.

Tunneled peripherally inserted central catheters (PICC) have potential to reduce complications compared to non-tunneled PICC in previous studies. Which is better is debatable. Thus, the aim to compare the effect of tunneled and non-tunneled PICC for cancer patients undergoing chemotherapy. Embase, PubMed, Cochrane Library database, and CNKI were searched from inception to March 15, 2024. Odds ratios (ORs) with 95% confidence intervals (95% CIs) was calculated to assess the complications of tunneled and non-tunneled PICC for cancer patients undergoing chemotherapy using random- or fixed-effects models. A total of 12 articles were retrieved. Meta-analysis showed that tunneled PICC significantly decreased the risk of wound oozing (OR: 0.29, 95% CI: 0.20-0.41), infection risk (OR: 0.41, 95% CI: 0.20-0.85), thrombosis risk (OR: 0.26, 95% CI: 0.15-0.44), phlebitis risk (OR: 0.23, 95% CI: 0.13-0.40), and catheter dislodgement risk (OR: 0.33, 95% CI: 0.22-0.50) compared to non-tunneled PICC. The subcutaneous tunneling technology has advantages over normal technique in decreasing PICC-related complications for cancer patients undergoing chemotherapy. PROSPERO (CRD42024522862).

Effects of the COVID-19 pandemic on maternal-fetal outcomes in a nonepidemic designated hospital: a retrospective study and clinical experience summary

ObjectiveTo assess the changes in maternal-fetal outcomes in a nonepidemic designated hospital during the COVID-19 pandemic.MethodsThis retrospective cohort study was conducted between January 1, 2019, and December 31, 2021 on pregnant patients. The fixed-effects regression model was used to determine changes in birth outcomes and pregnancy-related complications between three periods with the pre-epidemic cohort as the control group. Logistic regression was applied to determine the odds ratio (OR) for binary outcomes.ResultsThere were 15,261 births during the pre-epidemic period, and this number decreased by 15% and 23% to 12,980 and 11,736 in the first and second epidemic cohorts, respectively. The mean birth weight during the pre-epidemic period was 3319 which decreased to 3309 and 3272 g in the following periods. Excluding stillbirth and preterm, all other outcomes differed significantly between the three periods. Gestational diabetes mellitus (GDM) (17–19%) and maternal hypertension (9.2–11%) appeared to increase. Compared to the pre-epidemic period, the odds of macrosomia and LGA significantly decreased in the second epidemic cohort (adjusted ORs: 0.76 and 0.8), while the odds of low birth weight (LBW) and small gestation age (SGA) increased (ORs: 1.25 and 1.16). The odds of neonatal asphyxia (OR: 1.4), and hypertension (OR: 1.29) appeared to increase in the second epidemic cohort, while GDM decreased in the first cohort (OR: 0.88) and increased in the second cohort (OR: 1.15). Vaginal delivery underwent a marginal decrease in both the first and second epidemic cohorts (ORs: 0.89 and 0.92).ConclusionThe COVID-19 pandemic may have had a substantial and long-term impact on non-infected pregnant women and newborns. Our research results provided precious research information and clinical experience summary for population health research in the future.

Women’s Presence on Boards and Financial Performance: Evidence from Southeast Asia

The purpose of this article is to assess the impact of female board representation on financial performance in Southeast Asia. To compare the presence of women, three proxies are used: the percentage of women, the Blau Index, and the Shannon Index. The samples for five-year intervals (2017-2021) include 249 Southeast Asian enterprises and 1,245 observations. The Fixed Effect Model results show that, based on all three proxies, women's board participation leads to lower financial performance, which contradicts the Agency and Resource Dependence Theories. This document serves as a resource for regulators and stakeholders in developing effective and proper corporate governance, particularly in board compositions that need a proportion of women in Southeast Asia. The conclusions of this study may be impacted.

The Impact of Education Level on Real Estate Asset Allocation

As an important asset class, the allocation decision of real estate is of great significance to the wealth accumulation of individuals and families. This paper builds a theoretical framework based on the theoretical perspective of human capital, takes the CHFS database in 2015,2017 and 2019 as the benchmark, and constructs the Probit model, two-way fixed effect model and intermediary effect model to carry out empirical testing, revealing the causal relationship and mechanism between education level and real estate asset allocation. The results show that the education level significantly increases the individual real estate asset allocation, and this causality is still significantly established under multiple robustness tests. Financial information attention and financial knowledge play an important intermediary role in this process. In addition, the impact of educational level on real estate asset allocation was more obvious in the urban sample than in the rural groups. This study not only enriches the theoretical basis of relevant fields, but also provides a scientific basis for policy makers, which helps to optimize the allocation of resources in the real estate market and promote the sustainable economic development.

Effects and mechanisms of digitalization to enhance the resilience of the hog breeding industry: evidence from China

IntroductionWith the rapid development of digital agriculture, digitalization has gradually become a key factor affecting the resilience of China’s pig farming industry.MethodsFrom both the test results and the theoretical point of view, the individual fixed-effect model is more suitable for this paper’s study. Therefore, based on the panel data of 31 provinces in China from 2011 to 2022, this study constructs an individual fixed-effect model to examine how digitization affects the resilience of China’s pig farming industry.Results and discussionThe findings indicated that digitization significantly enhanced the resilience of China’s hog breeding industry, especially in potential growth areas. Improving breeding technology and scale is a crucial avenue for digitalization to bolster the industry’s resilience. Digitalization exerts a double threshold effect on the industry’s resilience, with its promotional impact only realized within a specific range. The article proposes policy suggestions, such as strengthening infrastructure construction and giving play to regional advantages.

Exploring the market resilience of selected stocks in the Johannesburg Stock Exchange

The market resilience of a stock is an integral component of financial market because it supports smooth trading and absorb market shocks. However, the contention has always been to effectively determine the level of resilience in stocks with the application of proper methodology to make informed decisions. Therefore, aim of this study was to examine the level of market resilience in selected stocks in the Johannesburg stock exchange. Using a fixed effect model, the findings of this study indicates that most securities trading on the exchange lack market resilience. This was evident in the significant relationship between the specific independent and dependent variables. A risk coefficient should therefore be assigned to bid and ask to spread to enhance market resilience. These risk coefficients will induce the bid and ask prices to be close to the fundamental price.

The Impact of ESG Performance on the Financial Performance of Chinese High-Tech and Internet Industry Firms

This study aims to explore the impact of Environmental, Social, and Governance (ESG) performance on the financial performance of firms in China’s high-tech and internet industries. Using annual data from 100 companies spanning from 2015 to 2022, a fixed effects model is applied for empirical analysis. The study finds that overall ESG performance has a significant positive impact on firms' return on assets (ROA) and net profit margin (NPM), with the governance (G) and social (S) dimensions showing particularly strong effects. While the environmental (E) dimension has a weaker short-term impact on financial performance, its long-term benefits are undeniable. Firm size and market share also have significant positive effects on financial performance. The results suggest that optimizing governance structures and actively fulfilling social responsibilities can enhance financial performance, while long-term investments in environmental responsibility should be integrated into corporate strategies. Overall, the findings provide empirical evidence for companies in formulating ESG strategies and offer specific policy recommendations for the sustainable development of China’s high-tech and internet industries.

Institutional quality and economic growth in upper-middle-income African countries

PurposeTo determine which proxy institutional quality variables are most significant for a country’s economic growth, the paper aims to investigate the effect of institutional quality on economic growth in upper-middle-income African nations between 2002 and 2021.Design/methodology/approachIn an attempt to account for countries' heterogeneity, the study uses a random and fixed effect model estimated by the generalized least squares.FindingsThe empirical findings demonstrate that the institutional quality measures of political stability, voice and accountability, corruption control and violence absence are statistically and favorably significant factors influencing the economic growth of upper-middle-income African countries.Originality/valueThis paper is unique in that it uses both random and fixed effects models to determine the effect of institutional quality on economic growth in the context of upper-middle-income African countries between 2002 and 2021.

The impact of foreign direct investment inflows on unemployment and economic growth in West Africa

Purpose: This study explores the short- and long-run effects of foreign direct investment inflows (FDI) on both the unemployment rate and economic growth in West Africa utilizing a panel dataset spanning from 1991 to 2022. The precise impact of FDI on these variables and the underlying factors shaping this relationship in West Africa has not been definitively delineated. Previous literature has not exclusively delved into the impact of FDI on the unemployment rate in this region. Consequently, our paper endeavors to address this particular gap in knowledge concentrating on the individual countries within West Africa. Design/Methodology/Approach: We employ Pooled Mean Group (PMG) estimators and fixed effects models for our analyses. Findings: Our findings based on the PMG models unveil that FDI exhibits an insignificant positive long-term effect and a highly significant negative short-term impact on economic growth in West Africa. Similarly, we observe that the impact of FDI on the unemployment rate is negative both in the long- and short-term. Conclusion: Our findings demonstrate that various factors contribute to how FDI influences the unemployment rate and economic growth rate in West Africa. Research Limitation: The results of these models analyses are subject to the considered economic variables. Other economic variables could give different results. Practical Implication: The research findings imply that FDI cannot be relied upon as a comprehensive strategy to either stimulate economic growth or alleviate unemployment in the Western Africa region.

Firm characteristics and corporate governance of state-owned enterprises: An analysis of an emerging market

This paper explores the relationship between firm-level factors and the quality of corporate governance of state-owned enterprises (SOEs) in an emerging economy, namely Vietnam. We employ a self-built corporate governance index (CGI) for SOEs and conduct an empirical analysis of data from 113 listed SOEs on the stock market of Vietnam from 2016-2020 using a fixed effect model (FEM) as suggested by the Hausman test. We find that firm-level characteristics such as firm age and tangibility of assets as well as macroeconomic factors such as the quality of the business climate and economic growth exhibit a statistically significant correlation with the corporate governance quality of SOEs. On the other hand, there is no established statistically significant relationship between other firm characteristics such as firm size, state ownership, financial leverage, growth opportunities and corporate governance. These results for an emerging economy like Vietnam are novel and provide implications for policymakers, regulators, shareholders and other stakeholders on the possibility of enhancing the quality of corporate governance of SOEs in an emerging market, a critical issue given the increasing role of SOEs in economies. Our research can be improved for future research in a couple of aspects. First, addressing the case of companies that do not disclose their governance practices in annual reports would help enhance the information for the corporate governance index. Second, extending the data to compare listed SOEs with other listed firms would provide a more comprehensive analysis.

Efficacy and safety of short segment pedicle screw fixation in patients with neurologically intact burst fractures of the lower thoracic and lumbar spine: a meta-analysis of studies published over the last 20 years

Objective. To conduct a systematic review and meta-analysis of studies on the surgical treatment of patients with uncomplicated burst fractures of the lower thoracic and lumbar spine and to determine the effectiveness and safety of short transpedicular fixation (TPF) in this patient group.Material and Methods. The study included articles with the following criteria: publication date from January 1, 2004, to December 31, 2023; patient sample descriptions involving uncomplicated burst fractures from T10 to L5; TPF involving one segment adjacent to the fractured vertebra in both cranial and caudal directions without spinal fusion; descriptions of treatment outcomes or complications; and an average follow-up period of at least 12 months. Meta-analysis was conducted using the Comprehensive Meta-Analysis software, version 2.2.064. Depending on the level of heterogeneity (I² test), either a fixed-effects or random-effects model was applied. Begg’s or Egger’s test was used to assess publication bias, and any bias present was corrected using the trim-and-fill method.Results. The application of TPF resulted in a significant reduction in the overall Cobb angle by 5.9 degrees in the percutaneous group and by 7.6 degrees when using a midline approach. Regarding AVBCR (anterior vertebral body compression ratio), a reduction of 24.0 % and 24.8 % was observed in both groups, respectively. The overall complication rates were as follows: superficial infection, 2.2 %; deep infection, 2.0 %; and implant-associated complications, 5.6 %. No patient developed a neurological deficit. The levels of work adaptation W1 and W2 on the Denis scale were achieved in 70.9 % of patients. The overall quality of life, as measured by the Oswestry Disability Index, averaged 13.4 %.Conclusions. Short transpedicular fixation without additional spinal fusion or laminectomy appears to be an effective and safe method for treating burst fractures of the lower thoracic and lumbar spine without neurological deficits. This method allows for regression of kyphotic deformity in the long-term post-injury period by at least 5.9 degrees and restoration of anterior vertebral height by 24 %. The approach demonstrated relatively low overall postoperative complication rates. More than 90 % of patients were able to return to full-time work, either in their previous position or with reduced physical demands.

Prognostic significance of the modified Glasgow Prognostic Score in NSCLC patients undergoing immune checkpoint inhibitor therapy: a meta-analysis.

The modified Glasgow Prognosis Score (mGPS), which considers both inflammatory response and nutritional status, has been linked to the prognosis of various tumors. The relationship between mGPS and non-small cell lung cancer (NSCLC) patients receiving immune checkpoint inhibitors (ICIs) is still a subject of debate. This meta-analysis aims to comprehensively assess the association between mGPS and survival in NSCLC treated with ICIs. A thorough review of studies from PubMed, Web of Science, Scopus, and Embase was conducted up to June 4, 2024. Fixed-effect or random-effect models were employed, combining hazard ratios (HRs) and 95% confidence intervals (CI), to assess the prognostic value of mGPS for OS and PFS in patients with NSCLC receiving immunotherapy. A total of 1,022 patients from 11 studies were recruited. Combined results showed that mGPS elevation was significantly associated with poor OS (HR = 1.63, 95%CI: 1.42-1.87, P < 0.01) and PFS (HR = 1.71, 95%CI: 1.31-2.24, P < 0.01). Subgroup analysis and sensitivity analysis further determined the predictive effect of elevated mGPS on OS and PFS deterioration in NSCLC patients receiving immunotherapy. mGPS can be used as a good noninvasive biomarker to demonstrate prognostic and clinical significance in patients with NSCLC undergoing immunotherapy. http://www.crd.york.ac.uk/prospero/ PROSPERO, identifier CRD42023432661.

DETERMINANTS OF INCOME INEQUALITY IN THE SELECTED GROUP OF EUROPEAN COUNTRIES: A PANEL DATA ANALYSIS

The paper focuses on providing basic characteristics of income inequality in a group of selected European countries in the period from 2000 to 2019. After presenting stylized facts and brief literature review, the paper proceeds to empirical analysis of income inequality in the observed countries by panel data techniques. Fixed and random effects models are estimated. After Hausman test approved the usage of fixed effects model, it was tested for serial correlation and robust standard errors were calculated. The empirical analysis of the determinants of income inequality shows that GDP growth, share of population in upper 10% of income percentile, Human Development Index and unemployment rate increase income inequality measured by Gini index, while share of workforce and share of population with tertiary education decrease income inequality. The results of the empirical analysis provide insight into determinants of income inequality, which may be useful for economic policy decision makers in their efforts to decrease the income inequality.

Macroeconomic Influences on Recycling in Europe: An Econometric Investigation

AbstractWhile the circular economy has garnered significant attention over the last two decades, few studies have explored the relationship between recycling and macroeconomic conditions. This paper aims to elucidate how macroeconomic factors influence and correlate with recycling indicators, focusing on European waste management. First, we analyze how macroeconomic indicators impact key circular economy indicators related to waste management, considering 27 European countries from 2000 to 2019, categorized into Western, Southern, and Eastern Europe. An ordinary least squares model serves as a baseline for comparison with a fixed effects model and a model with regional and time dummies. As a response to Ferrante and Germani's (2020) call for more research on causal studies of this kind, we also address reverse causality both by testing for panel data Granger causality and by applying the dynamic panel data approach developed by Arellano and Bond (1991). Second, we investigate variations in circular economic performance across European regions and countries, both before and after controlling for the macroeconomic context. The empirical analysis reveals a substantial correlation between circular economy indicators and key macroeconomic conditions, but we do not find evidence supporting causal impacts from macroeconomic circumstances in the short run. Regional examinations unveil disparities in circular economic performance, with Western Europe generally surpassing Southern and Eastern Europe. However, these patterns align more closely when considering the macroeconomic context. The methodologies employed in the study may prove valuable for future research on the circular economy and its relation to macroeconomic influences.

Exploring Client Preferences for Psychological Counselors in a Chinese Online Health Community: Longitudinal Study.

Although online health communities are acknowledged for their role in bridging the supply-demand gap in mental health services, the client decision-making process in these environments remains underexplored. This study aimed to explore the impact of different signals presented on psychological counselors' home pages on clients' choices. Adopting signaling theory as the framework, this study classified information into online and offline signals and developed a theoretical model to examine client choice behaviors. We collected data from 487 psychological counselors in a leading Chinese online mental health community during March, June, September, and December 2023. Based on these data, we constructed a 4-period balanced panel dataset. A fixed effects model was used to analyze which signals influence clients' choices of psychological counselors. Regarding online signals, the service price (β=0.186, P<.001) and online reputation (β=0.489, P=.002) of psychological counselors positively influence clients' choices. Concerning offline signals, psychological counselors' practical experience (β=0.007, P<.001) is positively related to clients' choices. Moreover, the results indicate that the relationship between a counselor's prosocial behavior and clients' choices is not linear but rather exhibits an inverted U-shape. This study reveals that the varied information provided by psychological counselors has distinct impacts on clients' choices in online health communities. It broadens the application of signaling theory to online behaviors and emphasizes the importance of both online and offline signals. These insights offer strategic guidance for counselors and online platforms to better meet potential clients' needs by optimizing the information presented on psychological counselors' home pages.

How ESG enhances corporate competitiveness: Mechanisms and Evidence

This paper uses data from Chinese A-share listed companies (2007∼2021) to investigate the impact of ESG performance on corporate competitiveness and its mechanism. Using a fixed-effects model, this paper finds that ESG performance significantly enhances corporate competitiveness. ESG exerts its influence by reducing financing constraints, enhancing corporate reputation, reducing agency conflicts, and promoting innovation. Heterogeneity analysis finds that firm size, financing convenience, local fiscal spending on science, and management ownership moderate this effect. This study enriches research on the drivers of corporate competitiveness and provides empirical support for long-term value investing in ESG in emerging markets.

The moderating effect of board gender diversity in the environmental sustainability and financial performance nexus

The study investigates the moderating effect of board gender diversity on the relationship between environmental performance indicators (emissions, innovations, and resources) and financial performance. The study adopts a robust research design, drawing on a diverse sample of 6,104 companies operating in various countries. It employs a sophisticated panel data analysis with a fixed-effect model. The findings indicate a significant effect of environmental performance on financial performance. The results also reveal that higher gender diversity on a board is linked to lower returns on assets (ROA). Moreover, there is a positive interaction between management teams, board gender diversity, and financial performance. This study explores the relationship between corporate governance, environmental performance, and financial outcomes, offering practical insights for businesses, policymakers, and stakeholders. It also provides actionable insights for companies to align sustainability practices with financial success, enhancing their environmental stewardship and potentially improving financial performance. Policymakers can use this knowledge to design regulations and guidelines, while stakeholders, including investors and environmental advocacy groups, can use it to make informed decisions. The study's originality lies in its exploration of the moderating impact of board diversity on the relationship between firms' environmental performance and financial performance, using a large sample from different countries. As there is still a lack of consensus on the effect of environmental performance on financial performance, this study contributes to the understanding of corporate governance, environmental responsibility, and financial performance.

Balancing customer and employee orientations: impact on financial distress and firm value

PurposeThis paper investigates the effect of balanced orientation (BO) toward customers and employees on financial distress and firm valuation. Rooted in stakeholder theory and the attention-based theory of firms, the study aims to understand how a balanced synthesis of employee orientation (EO) and customer orientation (CO) influences the long-term market performance and survivability of firms, particularly in the context of emerging markets.Design/methodology/approachA panel dataset of the top 500 firms listed on the National Stock Exchange of India was analyzed using fixed-effect panel models with robust estimators. The Heckman procedure was employed to address selection bias. Financial data were sourced from the CMIE Prowess database and balanced orientation data were extracted from the annual letters to shareholders.FindingsThe study finds that a balanced approach to EO and CO significantly lowers bankruptcy risk and increases firm valuation. Contrary to the traditional dichotomy of EO and CO, BO emerges as a key driver in reducing financial distress and enhancing long-term market performance. Firms embracing multiple strategic orientations outperform those solely focused on customer orientation.Practical implicationsFor emerging market firms facing resource constraints, developing BO is challenging but crucial. This study suggests adopting a sequential or alternating approach to developing EO and CO, which can alleviate bankruptcy risk and improve market valuation even in competitive environments.Originality/valueThis paper contributes to the existing literature by empirically demonstrating the significance of BO in emerging markets. It offers a novel perspective on strategic management, highlighting the importance of balancing customer and employee needs, especially in resource-constrained environments.

Risk management committee and earnings management: evidence from an emerging market

PurposeThis study examines whether the risk management committee (RMC) mitigates earnings management (EM) in Nigeria.Design/methodology/approachThe study used a sample of 365 firm-year observations of Nigerian-listed nonfinancial companies from 2018 to 2022. Driscoll and Kraay’s fixed-effect standard error regression model is used to test the hypotheses.FindingsThe study finds that RMC size, expertise, meeting frequency and membership overlapping with the audit committee have a negative effect on both accrual earnings management (AEM) and real earnings management (REM). While RMC independence is found to have a negative effect on REM. Moreover, additional tests reveal that RMC effectiveness is significantly associated with lower EM practices. Further analysis using the industry level finds that RMC attributes mitigate EM practices in some industries. The results remain after rigorous, robust analysis for endogeneity and alternative regressions.Research limitations/implicationsThis study is limited to a sample of Nigerian-listed nonfinancial service companies for a period of five years, resulting in the non-generalizability of the findings to different contexts as the countries’ internal policies and regulations varied.Practical implicationsThe findings have important implications for regulators, policymakers and investors that a stand-alone RMC can effectively help to evaluate potential risk activities and implement a proper risk management system, thereby mitigating EM practices. The result can help investors, analysts and other stakeholders across the international community in considering RMC information to evaluate potential risk and earnings management practices.Originality/valueFollowing the NCCG 2018 reform in Nigeria that requires listed firms to create a standalone RMC, this study is among the earliest that examines the effect of RMC attributes on EM practices and emerging markets. As such, the findings may draw the attention of regulators and policymakers across the African market and the international community to the monitoring role of RMC attributes in mitigating EM practices.