Potential Methodological Biases Research Articles

Personality Disorders and Suicide. A Systematic Review of Psychological Autopsy Studies.

This systematic review explores the relationship between personality disorders (PDs) and lethal suicide behavior. Following PRISMA guidelines, the study examines psychological autopsy studies with suicide deaths and identified PDs. Inclusion criteria encompass studies using the psychological autopsy method, reporting PD diagnosis and suicide deaths, in English language and with no temporal restrictions. The search strategy, conducted in PubMed and Embase until December 2nd, 2023, utilized specific terms related to suicide, PD, and psychological autopsy. Quality assessment using the Newcastle Ottawa-Scale for case-control studies was employed. 56 psychological autopsy studies were included in the systematic review, revealing a prevalence of PDs among suicide deaths, and emphasizing their role as significant suicide risk factors. The review underscores the impact of comorbid PDs and Axis I disorders on suicide risk, particularly if additional stressors are present. Gender differences in PD prevalence are noted, with impulsivity and alcohol abuse identified as universal risk factors. Despite extensive global data collection, limitations include potential methodological variations and biases inherent in psychological autopsy studies. This study, registered in PROSPERO (CRD42022322359), contributes essential insights into the prevalence, characteristics, and risk factors of PDs among suicide deaths.

Putting gluten back on menu - Safety assessment of polyphenol-rich wheat varieties in Celiac Disease.

This study provides a comprehensive proteomic and metabolomic analysis of novel anthocyanin- and carotenoid-rich wheat varieties to assess their immunogenicity in the context of Celiac Disease. Using (semi)-quantitative mass spectrometry, the research found that gliadin expression and peptide release, particularly those containing immunostimulatory γ-gliadin epitopes, vary significantly across different wheat varieties. While non-targeted mass spectrometry provided valuable insights, the study acknowledged potential methodological biases, such limitations of ion current intensity as a measure of peptide abundance. Despite promising results, further research is required to determine the safety and efficacy of coloured wheat varieties for Celiac Disease patients, considering the complex interplay of gluten proteins, food processing, digestion and matrix effects. The ongoing studies hold potential for developing nutritionally beneficial wheat alternatives for Celiac Disease management.

Are the best higher education institutions also more sustainable?

PurposeThe purpose of this study is to analyze the integration of sustainable practices in the strategies and operations of world-class higher education institutions (HEIs) under the theoretical guidance of Max Weber's instrumental and value rationalities.Design/methodology/approachThe results of the Quacquarelli-Symonds World University Ranking, Times Higher Education World University Rankings, THE Impact Rankings and GreenMetric World University Ranking rankings from 2019 to 2022 were paired, and the correlation between them was verified. Institutions with simultaneous occurrence in the four rankings in at least one of the years were also classified. A quantitative and qualitative methodology was used to explore how elite HEIs integrate sustainable practices into their operations and strategies, under the theoretical guidance of Max Weber's instrumental and value rationalities. Furthermore, multivariate regression models with supervised data mining techniques were applied, using the SMOReg algorithm on 368 instances with multiple attributes, to predict the numerical value of sustainability in the rankings. Coefficients were assigned to variables to determine their relative importance in predicting rankings.FindingsThe results of this study suggest that although many HEIs demonstrate a commitment to sustainability, this rarely translates into improvements in traditional rankings, indicating a disconnect between sustainable practices and global academic recognition.Research limitations/implicationsThe research has limitations, including the analysis being restricted to data from specific rankings between 2019 and 2022, which may limit generalization to future editions or rankings. The predictive models used selected data and, therefore, cannot cover the full complexity of metrics from other rankings. Furthermore, internal factors of HEIs were not considered, and the correlations identified do not imply direct causality. The limited sample and potential methodological biases, together with the heterogeneity of the rankings, restrict the generalization of the results. These limitations should be considered in future studies.Practical implicationsThe theoretical contributions of this study include an in-depth understanding of the intersection between academic excellence and environmental and social responsibility. From a management perspective, guidance is provided on integrating sustainability into HEI strategies to enhance visibility and classification in global rankings, while maintaining academic integrity and commitment to sustainability.Social implicationsThis highlights the importance of reassessing academic rankings criteria to include sustainability assessments, thereby encouraging institutions to adopt practices that genuinely contribute to global sustainable development.Originality/valueThe originality lies in the predictive analysis between these rankings, examining the link between the level of sustainability of an HEI and its classification as a World Class University. Furthermore, it combines theories of rationality with the analysis of sustainability integration in elite HEIs, introducing new analytical perspectives that can influence future educational policies and institutional practices.

Crowd-funding to promote women entrepreneurship: a systematic literature review of the empirical studies conducted in the last decade (2012–2023)

PurposeIt aims to understand crowdfunding’s effect on women’s entrepreneurship and summarize key findings, methods, and challenges women face in using crowdfunding for financing.Design/methodology/approachThis literature review examines 36 empirical studies on crowdfunding use by women entrepreneurs. It follows the PRISMA framework, using Scopus and citation tracking to categorize studies on crowdfunding’s potential to empower women financially and address their barriers to accessing finance.FindingsThe review identified seven key themes: opportunities and challenges for women in crowdfunding, equity crowdfunding’s potential, gender differences in crowdfunding outcomes, the role of social capital and networks, investor trust and decision-making, the influence of language, communication, and platform design, and the importance of considering intersectionality and context. Crowdfunding offers women entrepreneurs access to capital and helps them overcome traditional financing barriers. Women-led campaigns achieve comparable or even higher success rates compared to their male counterparts. However, under-representation, lower funding requests, pitching difficulties, and limited access to networks remain as challenges.Research limitations/implicationsThis study has limitations inherent to systematic reviews, including potential methodological flaws or biases in the included studies and the exclusion of relevant studies due to time and resource constraints.Practical implicationsCrowdfunding can be promoted as a viable financing option for women entrepreneurs and design targeted initiatives to support them. Building social capital, enhancing financial literacy, and creating networking opportunities can contribute to their success in navigating crowdfunding platforms effectively.Originality/valueThis review offers a comprehensive analysis of empirical studies conducted between 2012 and 2023. It provides up-to-date insights, identifies key themes, and offers actionable recommendations for policymakers and organizations seeking to support women entrepreneurs in effectively accessing and utilizing crowdfunding platforms.

Modeling longitudinal relationships between sleep disturbances and depressed mood in postpartum: A cross-lagged panel design

BackgroundThis short communication explores the interrelationships between depressed mood and sleep disturbances in one-year postpartum period. MethodsUtilizing data from the Interaction of Gene and Environment of Depression during PostPartum Cohort (IGEDEPP) involving 3310 French postpartum women, we employed a cross-lagged panel model (CLPM) to analyze the relationships between these two symptoms, across three time points (immediate postpartum [<1 week after delivery], early postpartum [<2 months after delivery], and late postpartum [2 months to 1 years after delivery]). ResultsDepressed mood significantly influences sleep disturbances in late postpartum (β = 0.096, z-value = 7.4; p < 0.001) but not in early postpartum (p-value = 0.9). We found no cross-lagged influence of sleep disturbances on depressed mood in early (p = 0.066) or in late postpartum (p = 0.060). Moreover, depressed mood and sleep disturbances in immediate postpartum are predictive of similar symptoms in the two other postpartum periods (between each of the three periods, p = 0.006 and p < 0.001 for depressed mood, and p = 0.039 and p < 0.001 for sleep disturbances), thus demonstrating the stability of these symptoms over time. LimitationsAlthough conducted with a prospectively assessed cohort, this study faces limitations due to potential methodological biases. ConclusionsThis study is a pioneering analysis of mutual causal interactions between depressed mood and sleep disturbances in the postpartum period, highlighting the need for vigilant monitoring, early detection, prevention of worsen outcomes and intervention on these symptoms.

Planktonic Marine Fungi: A Review

AbstractFungi in marine ecosystems play crucial roles as saprotrophs, parasites, and pathogens. The definition of marine fungi has evolved over the past century. Currently, “marine fungi” are defined as any fungi recovered repeatedly from marine habitats that are able to grow and/or sporulate in marine environments, form symbiotic relationships with other marine organisms, adapt and evolve at the genetic level, or are active metabolically in marine environments. While there are a number of recent reviews synthesizing our knowledge derived from over a century of research on marine fungi, this review article focuses on the state of knowledge on planktonic marine fungi from the coastal and open ocean, defined as fungi that are in suspension or attached to particles, substrates or in association with hosts in the pelagic zone of the ocean, and their roles in remineralization of organic matter and major biogeochemical cycles. This review differs from previous ones by focusing on biogeochemical impacts of planktonic marine fungi and methodological considerations for investigating their diversity and ecological functions. Importantly, we point out gaps in our knowledge and the potential methodological biases that might have contributed to these gaps. Finally, we highlight recommendations that will facilitate future studies of marine fungi. This article first provides a brief overview of the diversity of planktonic marine fungi, followed by a discussion of the biogeochemical impacts of planktonic marine fungi, and a wide range of methods that can be used to study marine fungi.

Supporting academic achievement of children in out-of-home care through effective interventions: results of a systematic review and meta-analyses

As students in out-of-home care are at high risk of school failure, it is imperative to promote academic skills through effective interventions. A systematic review of interventions aimed at improving academic achievement of out-of-home care was conducted to identify the most effective strategies for supporting literacy and mathematical skills. Data from 21 interventions, involving 2,049 children in out-of-home care, were synthesized through meta-analysis. Overall, the interventions had a significant impact on literacy (g = .242, 95 % CI [.180, .305], k = 21) and mathematical skills (g = .229, 95 % CI [.115, .343], p <.001, k = 14). Three main direct academic support strategies were compared to determine if one was superior to the others: tutoring, individualized support, and distribution of academic material. The results of subgroup analysis failed to detect any differences between effect sizes, most likely due to low statistical power. Thus, the main trends were discussed. Tutoring, as the most rigorously evaluated intervention, appeared to outperform other types of intervention strategies, especially in respect to mathematical skills, where the results remained robust despite potential methodological bias. However, it is essential to consider significant limitations when interpreting these results. Implications for practice and research are discussed.

Impacts of sea ice melting procedures on measurements of microbial community structure

Microorganisms play critical roles in sea ice biogeochemical processes. However, microbes living within sea ice can be challenging to sample for scientific study. Because most techniques for microbial analysis are optimized for liquid samples, sea ice samples are typically melted first, often applying a buffering method to mitigate osmotic lysis. Here, we tested commonly used melting procedures on three different ice horizons of springtime, first year, land-fast Arctic sea ice to investigate potential methodological impacts on resulting measurements of cell abundance, photophysiology, and microbial community structure as determined by 16S and 18S rRNA gene amplicon sequencing. Specifically, we compared two buffering methods using NaCl solutions (“seawater,” melting the ice in an equal volume of 35-ppt solution, and “isohaline,” melting with a small volume of 250-ppt solution calculated to yield meltwater at estimated in situ brine salinity) to direct ice melting (no buffer addition) on both mechanically “shaved” and “non-shaved” samples. Shaving the ice shortened the melting process, with no significant impacts on the resulting measurements. The seawater buffer was best at minimizing cell lysis for this ice type, retaining the highest number of cells and chlorophyll a concentration. Comparative measurements of bacterial (16S) community structure highlighted ecologically relevant subsets of the community that were significantly more abundant in the buffered samples. The results for eukaryotic (18S) community structure were less conclusive. Taken together, our results suggest that an equivalent-volume seawater-salinity buffered melt is best at minimizing cell loss due to osmotic stress for springtime Arctic sea ice, but that either buffer will reduce bias in community composition when compared to direct melting. Overall, these findings indicate potential methodological biases that should be considered before developing a sea ice melting protocol for microbiological studies and afterwards, when interpreting biogeochemical or ecological meaning of the results.

Critical appraisal in ecology: What tools are available, and what is being used in systematic reviews?

Many reviews referred to as 'systematic reviews' in ecology are not consistent with best practice in that they generally lack appropriate critical appraisal of included studies. This limitation is particularly important in applied ecology, where there have been increasing calls for more systematic reviews to guide decision making. To identify the available critical appraisal tools (CATs) and hierarchies of evidence available for ecology studies, we systematically searched for: studies that described the development and/or examination of tools to assess the potential methodological bias in studies of ecology; and the tools used to assess potential methodological bias of included studies in ecological systematic reviews. We identified 680 reviews labelled as 'systematic reviews' in ecology, however only 4.0% performed critical appraisal of the included studies. Three hierarchies of evidence and 23 CATs were identified, and assessed as lacking independent development, validity and reliability testing, and/or completeness. The authors of the reviews that included critical appraisal have appropriately identified the need to move reviews in ecology in the direction of this higher level of evidence, and have taken applied ecology further in the direction of evidence-based practice. However, we identified shortcomings in these approaches when compared with best practice, and conclude that new tools are needed that reflect a range of questions posed in ecology. Through increasing the availability of such tools, the strength of evidence provided by systematic reviews in ecology would improve.

Antiherpetic drugs: a potential way to prevent Alzheimer\u2019s disease?

BackgroundConsidering the growing body of evidence suggesting a potential implication of herpesviruses in the development of dementia, several authors have questioned a protective effect of antiherpetic drugs (AHDs) which may represent a new means of prevention, well tolerated and easily accessible. Subsequently, several epidemiological studies have shown a reduction in the risk of dementia in subjects treated with AHDs, but the biological plausibility of this association and the impact of potential methodological biases need to be discussed in more depth.MethodsUsing a French medico-administrative database, we assessed the association between the intake of systemic AHDs and the incidence of (i) dementia, (ii) Alzheimer’s disease (AD), and (iii) vascular dementia in 68,291 subjects over 65 who were followed between 2009 and 2017. Regarding potential methodological biases, Cox models were adjusted for numerous potential confounding factors (including proxies of sociodemographic status, comorbidities, and use of healthcare) and sensitivity analyses were performed in an attempt to limit the risk of indication and reverse causality biases.Results9.7% of subjects (n=6642) had at least one intake of systemic AHD, and 8883 incident cases of dementia were identified. Intake of at least one systemic AHD during follow-up was significantly associated with a decreased risk of AD (aHR 0.85 95% confidence interval [0.75–0.96], p=0.009) and, to a lesser extent with respect to p values, to both dementia from any cause and vascular dementia. The association with AD remained significant in sensitivity analyses. The number of subjects with a regular intake was low and prevented us from studying its association with dementia.ConclusionsTaking at least one systemic AHD during follow-up was significantly associated with a 15% reduced risk of developing AD, even after taking into account several potential methodological biases. Nevertheless, the low frequency of subjects with a regular intake questions the biological plausibility of this association and highlights the limits of epidemiological data to evaluate a potential protective effect of a regular treatment by systemic AHDs on the incidence of dementia

Evaluation of biological nitrogen fixation in coarse woody debris from Eastern Canadian boreal forests

The contribution of Coarse Woody Debris (CWD) to N inputs in boreal ecosystems has been reported in intensively managed Scandinavian forests in Europe and in Pacific coastal rainforest in North America. These estimates range from 0.085 to 2 kg N ha−1 y−1. Data from Eastern Canadian forests that receive fewer sylvicultural treatments than do Scandinavian forests and are exposed to a drier climate than the Canadian rainforest are scare. We evaluated contributions of CWD to total BNF in two forest sites dominated by balsam fir and black spruce. We also measured the conversion ratio (R ratio = ARA/N2) for the acetylene reduction assay, which is the method most often used to estimate N2-fixation, using parallel 15N2 incubations to account for potential methodological biases. We further tested two factors that can affect the R ratio, hance quality of BNF estimates in deadwood; inhibition of N2-fixing methanotrophs by acetylene and molybdenum limitation of N2-fixation. We report that N2-fixation by CWD in balsam fir and black spruce from eastern boreal forest is low (0.05–0.12 kg N ha−1y−1) compared to other estimates for coniferous forests. We also show that moss-covered CWD can significantly contribute to CWD N2-fixation and that improper validation of the ARA can lead to significant underestimation of N inputs.

Clinical preventive guidelines for school-aged children and adolescents in primary care: a protocol for a systematic review

IntroductionGuidelines for clinical preventive services targeting school-aged children and adolescents in primary care are limited, often inconsistent and difficult to apply in clinical contexts. This publication describes the protocol concerning...

Association Between Alzheimer Disease and Cancer With Evaluation of Study Biases

Observational studies consistently report inverse associations between cancer and Alzheimer disease (AD). Shared inverse etiological mechanisms might explain this phenomenon, but a systematic evaluation of methodological biases in existing studies is needed. To systematically review and meta-analyze evidence on the association between cancer and subsequent AD, systematically identify potential methodological biases in studies, and estimate the influence of these biases on the estimated pooled association between cancer and AD. All-language publications were identified from PubMed, Embase, and PsycINFO databases through September 2, 2020. Longitudinal cohort studies and case-control studies on the risk of AD in older adults with a history of any cancer type, prostate cancer, breast cancer, colorectal cancer, or nonmelanoma skin cancer, relative to those with no cancer history. Two reviewers independently abstracted the data and evaluated study biases related to confounding, diagnostic bias, competing risks, or survival bias. Random-effects meta-analysis was used to provide pooled estimates of the association between cancer and AD. Metaregressions were used to evaluate whether the observed pooled estimate could be attributable to each bias. The study was designed and conducted according to the Preferring Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Incidence, hazard, or odds ratios for AD comparing older adults with vs without a previous cancer diagnosis. In total, 19 cohort studies and 3 case-control studies of the associations between any cancer type (n = 13), prostate cancer (n = 5), breast cancer (n = 1), and nonmelanoma skin cancer (n = 3) with AD were identified, representing 9 630 435 individuals. In all studies combined, cancer was associated with decreased AD incidence (cohort studies: random-effects hazard ratio, 0.89; 95% CI, 0.79-1.00; case-control studies: random-effects odds ratio, 0.75; 95% CI, 0.61-0.93). Studies with insufficient or inappropriate confounder control or greater likelihood of AD diagnostic bias had mean hazard ratios closer to the null value, indicating that these biases could not explain the observed inverse association. Competing risks bias was rare. Studies with greater likelihood of survival bias had mean hazard ratios farther from the null value. The weak inverse association between cancer and AD may reflect shared inverse etiological mechanisms or survival bias but is not likely attributable to diagnostic bias, competing risks bias, or insufficient or inappropriate control for potential confounding factors.

Multicenter assessment of microbial community profiling using 16S rRNA gene sequencing and shotgun metagenomic sequencing

IntroductionMicrobiome research based on high-throughput sequencing has grown exponentially in recent years, but methodological variations can easily undermine the reproducibility across studies. ObjectivesTo systematically evaluate the comparability of sequencing results of 16S rRNA gene sequencing (16Ss)- and shotgun metagenomic sequencing (SMs)-based microbial community profiling in laboratories under routine conditions. MethodsWe designed a multicenter study across 35 participating laboratories in China using designed mock communities and homogenized fecal samples. ResultsA wide range of practices and approaches was reported by the participating laboratories. The observed microbial compositions of the mock communities in 46.2% (12/26) of the 16Ss and 82.6% (19/23) of the SMs laboratories had significant correlations with the expected result (Spearman r>0.59, P <0.05). The results from laboratories with near-identical protocols showed slight interlaboratory deviations. However, a high degree of interlaboratory deviation was found in the observed abundances of specific taxa, such as Bacteroides spp. (range: 0.3%-53.5%), Enterococci spp. (range: 0.8%-43.9%) and Fusobacterium spp. (range: 0.1%-39.8%). SMs performed better than 16Ss in detecting low-abundance bacteria (B. bifidum). The differences in DNA extraction methods, amplified regions and bioinformatics analysis tools (taxonomic classifiers and database) were important factors causing interlaboratory deviations. Addressing laboratory contamination is an urgent task because various sources of unexpected microbes were found in negative control samples. ConclusionsWell-defined control samples, such as the mock communities in this study, should be routinely used in microbiome research for monitoring potential biases. The findings in this study will provide guidance in the choice of more reasonable operating procedures to minimize potential methodological biases in revealing human microbiota composition.

Methodological and physical biases in global to subcontinental borehole temperature reconstructions: an assessment from a pseudo-proxy perspective

Abstract. Borehole-based reconstruction is a well-established technique to recover information of the past climate variability based on two main hypotheses: (1) past ground surface temperature (GST) histories can be recovered from borehole temperature profiles (BTPs); (2) the past GST evolution is coupled to surface air temperature (SAT) changes, and thus, past SAT changes can be recovered from BTPs. Compared to some of the last millennium (LM) proxy-based reconstructions, previous studies based on the borehole technique indicate a larger temperature increase during the last few centuries. The nature of these differences has fostered the assessment of this reconstruction technique in search of potential causes of bias. Here, we expand previous works to explore potential methodological and physical biases using pseudo-proxy experiments with the Community Earth System Model Last Millennium Ensemble (CESM-LME). A heat-conduction forward model driven by simulated surface temperature is used to generate synthetic BTPs that are then inverted using singular value decomposition. This procedure is applied to the set of simulations that incorporates all of the LM external forcing factors as well as those that consider the concentration of the green house gases (GHGs) and the land use land cover (LULC) changes forcings separately. The results indicate that methodological issues may impact the representation of the simulated GST at different spatial scales, with the temporal logging of the BTPs as the main sampling issue that may lead to an underestimation of the simulated GST 20th-century trends. Our analysis also shows that in the surrogate reality of the CESM-LME the GST does not fully capture the SAT warming during the industrial period, and thus, there may be a further underestimation of the past SAT changes due to physical processes. Globally, this effect is mainly influenced by the GHG forcing, whereas regionally, LULC changes and other forcings factors also contribute. These findings suggest that despite the larger temperature increase suggested by the borehole estimations during the last few centuries of the LM relative to some other proxy reconstructions, both the methodological and physical biases would result in a underestimation of the 20th-century warming.

Is Sociability or Interactivity more Effective for Enhancing Performance? Findings from a Massively Multiplayer Online Role-Playing Game

The essential issue currently challenging marketing managers in the virtual world is: How can a virtual world feature be designed to elevate consumers' purchase of virtual items and usage in the virtual world? Previous scholars have investigated the issue and have published their predictions on the individual level. Yet, they have done so without specifically addressing endogeneity or carryover effect among users and their activities. To alleviate this omission and potential methodological bias, we probe the impact of virtual world technological features on two performance criteria at the platform level. In addition, we differentiate two types of users (new vs returning users) and probe their distinct impact on purchase of virtual items and usage patterns in the virtual world. When using data from one virtual world and applying the vector auto regression model, results show that virtual world managers can elevate performance through promotion of both types of users' activities. The effects of these activities, however, are varied. Specifically, for returning users, interactivity leads to a more significant impact on consumers' purchase of virtual goods than sociability, while the opposite effect is applicable to usage in the virtual world. For new users, interactivity is more efficient for promotion of users' purchase of virtual goods than sociability, while the results are the opposite for usage in the virtual world.

Yoga for Osteoarthritis: a Systematic Review and Meta-analysis.

This study aims to systematically review and summarise the efficacy and safety of yoga for osteoarthritis. Medline (through PubMed), Scopus, and the Cochrane Library were searched through April 2018 for randomised controlled trials of yoga for osteoarthritis. Primary outcomes were pain intensity, function, and quality of life; secondary outcomes were mental health and safety. Risk of bias was assessed using the Cochrane tool and quality of evidence through GRADE. Nine trials including 640 individuals with mainly lower extremity osteoarthritis aged 50-80years were identified, with 80.3% female participants (median). Meta-analyses revealed very low-quality evidence for the effects of yoga on pain (vs. exercise: standardised mean difference (SMD) = - 1.07; 95%CI - 1.92, - 0.21; p= 0.01; vs. non-exercise: SMD = - 0.75; 95%CI - 1.18, - 0.31; p< 0.001), physical function (vs. exercise: SMD = 0.80; 95%CI 0.36; 1.24; p< 0.001; vs. non-exercise: SMD = 0.60; 95%CI 0.30, 0.98; p< 0.001), and stiffness (vs. exercise: SMD = - 0.92; 95%CI - 1.69, - 0.14; p= 0.008; vs. non-exercise: SMD = - 0.76; 95%CI - 1.26, - 0.26; p= 0.003) in individuals with knee osteoarthritis. Effects were not robust against potential methodological bias. No effects were found for quality of life, and depression, or for hand osteoarthritis. Safety was rarely reported. The findings of this meta-analysis indicate that yoga may be effective for improving pain, function, and stiffness in individuals with osteoarthritis of the knee, compared to exercise and non-exercise control groups. Due to the low methodological quality and potential risk of bias, only a weak recommendation can be made at this time for the use of yoga in adults with osteoarthritis of the knee.

Ranking Hospitality and Tourism Journals

Publications and reports on ranking journals are commonly found in various disciplines, including hospitality and tourism. They rank the journals on a list based on subjective judgment of experts and/or objective third-party indicators. The ranking of a journal represents its quality and prestige in the field. However, there exists no commonly agreed rankings of hospitality and tourism journals due to the different methods adopted. The current commentary critiques the relevance and accuracy of such rankings by revealing the potential methodological biases and limited implications in knowledge development.

Stratification by quality induced selection bias in a meta-analysis of clinical trials

ObjectivesThe inconsistency demonstrated across strata when using different scales has been attributed to quality scores, and stratification continues to be done using risk of bias domain judgments. This study examines if restricting primary meta-analyses to studies at low risk of bias or presenting meta-analyses stratified according to risk of bias is indeed the right approach to explore potential methodological bias. Study Design and SettingReanalysis of the impact of quality subgroupings in an existing meta-analysis based on 25 different scales. ResultsWe demonstrate that quality stratification itself is the problem because it induces a spurious association between effect size and precision within stratum. Studies with larger effects or lesser precision tend to be of lower quality—a form of collider-stratification bias (stratum being the common effect of the reasons for these two outcomes) that leads to inconsistent results across scales. We also show that the extent of this association determines the variability in effect size and statistical significance across strata when conditioning on quality. ConclusionsWe conclude that stratification by quality leads to a form of selection bias (collider-stratification bias) and should be avoided. We demonstrate consistent results with an alternative method that includes all studies.

Cancer and dementia: Two sides of the same coin?

Noncentral nervous system cancer and the brain share an interesting and complex relation, with an emerging body of evidence showing that cancer patients are at an increased risk of developing cognitive problems. In contrast, population‐based studies consistently find an inverse link between cancer and dementia, that is patients with dementia having a lower risk of subsequently developing cancer, and cancer patients being less often diagnosed with dementia. Different biological processes such as inversely activated cell proliferation and survival pathways have been suggested to have an important role underlying this inverse association. However, the effect of methodological biases including surveillance or survival bias has not been completely ruled out, calling into question the inverse direction of the association between cancer and dementia. In fact, emerging evidence now suggests that cancer and dementia might share a positive association. This narrative review summarises the current literature on cancer, cognitive problems and dementia. Moreover, different strategies will be discussed to reduce the impact of potential methodological biases on the association between cancer and dementia, trying to reveal the true direction of this link.