Substantive Effect Research Articles

Benchmark validation of statistical models: Application to mediation analysis of imagery and memory.

This article describes benchmark validation, an approach to validating a statistical model. According to benchmark validation, a valid model generates estimates and research conclusions consistent with a known substantive effect. Three types of benchmark validation-(a) benchmark value, (b) benchmark estimate, and (c) benchmark effect-are described and illustrated with examples. Benchmark validation methods are especially useful for statistical models with assumptions that are untestable or very difficult to test. Benchmark effect validation methods were applied to evaluate statistical mediation analysis in eight studies using the established effect that increasing mental imagery improves recall of words. Statistical mediation analysis led to conclusions about mediation that were consistent with established theory that increased imagery leads to increased word recall. Benchmark validation based on established substantive theory is discussed as a general way to investigate characteristics of statistical models and a complement to mathematical proof and statistical simulation. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Systemic administration of curcumin or piperine enhances the periodontal repair: a preliminary study in rats.

Studies have documented the anti-inflammatory effects of spices, which may be related to treatment of chronic diseases. The purpose of this study was to evaluate the influence of curcumin and piperine and their association on experimental periodontal repair in rats. Periodontitis was induced via the installation of a ligature around the first molar. After 15days, the ligatures were removed, and the rats were separated into groups (12 animals per group): (i) curcumin, (ii) piperine, (iii) curcumin+piperine, (iv) corn oil vehicle, and (v) control group (animals had ligature-induced periodontitis but were not treated). The compounds were administered daily, for 15days by oral gavage. Animals were euthanized at 5 and 15days, and hemimaxillae and gingival tissues were harvested. Bone repair was assessed by μCT (microcomputer tomography). Histological sections were stained with hematoxylin/eosin (H/E) for the assessment of cellular infiltrate or picrosirius red for quantification of collagen content, and subjected to immunohistochemistry for detecting NF-ĸB. Gingival tissues were used to evaluate levels of TGF-β and IL-10 (ELISA). Curcumin and piperine increased the TGF-β level, significantly improved the collagen repair, and decreased the cellularity and activation of NF-ĸB in the periodontal tissues, but only curcumin caused a significant increase in early bone repair. Curcumin and piperine promoted a substantive effect on tissue repair; however, there was not synergistic effect of compounds administered in combination. Curcumin and piperine stimulates the tissue repair and may be potential candidates for the treatment of periodontal disease.

Uncertainty in the effects of the modifiable areal unit problem under different levels of spatial autocorrelation: a simulation study

ABSTRACTThe objective of this paper is to investigate uncertainties surrounding relationships between spatial autocorrelation (SA) and the modifiable areal unit problem (MAUP) with an extensive simulation experiment. Especially, this paper aims to explore how differently the MAUP behaves for the level of SA focusing on how the initial level of SA at the finest spatial scale makes a significant difference to the MAUP effects on the sample statistics such as means, variances, and Moran coefficients (MCs). The simulation experiment utilizes a random spatial aggregation (RSA) procedure and adopts Moran spatial eigenvectors to simulate different SA levels. The main findings are as follows. First, there are no substantive MAUP effects for means. However, the initial level of SA plays a role for the zoning effect, especially when extreme positive SA is present. Second, there is a clear and strong scale effect for the variances. However, the initial SA level plays a non-negligible role in how this scale effect deploys. Third, the initial SA level plays a crucial role in the nature and extent of the MAUP effects on MCs. A regression analysis confirms that the initial SA level makes a substantial difference to the variability of the MAUP effects.

Could chlorhexidine be an adequate positive control for antimicrobial photodynamic therapy in- in vitro studies?

Chlorhexidine digluconate (CHX) is commonly applied as positive control of new antimicrobials, because it is considered the gold-standard for chemical plaque control. The aim of this study was to compare the effect of treatments with curcumin-mediated aPDT and CHX in relation to the viability of specific microorganism groups in two distinct times (immediately and 24 h later). Dentin caries microcosms were grown on bovine dentin discs (37 °C, anaerobiosis) for 3 days in the Active Attachment Amsterdam Biofilm Model. The biofilms were treated with 300 μM curcumin and 75 J.cm-² LED, or 0.06% and 0.12% CHX. Then, total microorganisms, total streptococci, mutans streptococci, and total lactobacilli counts were determined. The statistical analysis was conducted by Kruskal-Wallis and post-hoc Dunn's tests (P < 0.05). Curcumin-mediated aPDT (C + L+), 0.06% and 0.12% CHX reduced mutans streptococci counts (0.19, 0.10 and 0.07 log10 respectively) in the immediate analysis. After 24 h, it was observed a re-growth of microorganisms treated by curcumin-mediated aPDT, whereas both CHX concentrations demonstrated a decrease of the viable microorganisms. This study confirmed the substantive effect of CHX and the immediate effect of aPDT. The use of a neutralizer solution was important to block the substantivity of CHX and permit its fair comparison with aPDT, allowing its use as a positive control in further studies.

Assessing the influence of neutral grounds on match outcomes

ABSTRACTThe home advantage in various sports has been well documented. So far, we lack knowledge whether playing in neutral venues indeed removes many, if not all, theoretically assumed advantages of playing at home. Analysing over 3,500 senior men’s Gaelic football and hurling matches – field games with the highest participation rates in Ireland – between 2009 and 2018, we test the potential moderating influence of neutral venues. In hurling and Gaelic football, a considerable share of matches is played at neutral venues. We test the influence of neutral venues based on descriptive statistics, and multilevel logistic and multinomial regressions controlling for team strength, the importance of the match, the year, and the sport. With predicted probabilities ranging between 0.8 and 0.9, the favourite team is very likely to win home matches. The predicted probability drops below 0.6 for away matches. At neutral venues, the favourite team has a predicted probability of winning of 0.7. A Coarsened Exact Matching (CEM) approach also reveals very substantive and significant effects for the “treatment” of neutral venues. Overall, neutral venues appear to be an under-utilised option for creating fairer and less predictable competition, especially in single-game knock-out matches.

Decadal effects of thinning on understory light environments and plant community structure in a subtropical forest

AbstractCanopy‐opening disturbance such as thinning has immediate and substantive effects on understory microclimate and therefore the establishment and growth of understory plants. A large number of studies have reported the effects of thinning on tree growth, but few studies have examined long‐term effects of thinning on understory light environments and species and functional diversity of understory plants. Even less is known whether the change in understory plant community structure observed following canopy disturbance is short‐lived and would diminish as the canopy closes or a long lasting due to legacy effects. We examined the effects of an experimental removal of 25% and 50% of the woody vegetation on understory light availability and variability on understory plant community structure in a subtropical Cryptomeria japonica plantation nine years after the treatment. Differences in availability of understory light among treatments diminished nine years after the experimental vegetation removal (thinning), but variability of understory light was still two times higher in the thinned treatments than the un‐thinned control. Species diversity of dominant and common understory plants was lower in the control than in the two thinning treatments, which were not different from each other. Community species and functional composition were also different between the un‐thinned control and the two thinning treatments. The thinned plots had proportionally more individuals of grasses and forbs and fewer individuals of ferns. Our results indicate that the effects of thinning on understory light variability last longer than on light availability representing an important and long‐lasting alteration of resource heterogeneity. At both species and functional group levels, greater diversity and unique composition in the thinned treatments compared to undisturbed control suggest a link between resource heterogeneity and biodiversity in the forest understory or legacy effects associated with the thinning‐induced changes in understory plant community.

Risk Definition in Insurance Law: Significance and Challenges

The traditional common law approach to breach of an insurance contract term had been technical, and had given priority to the form of the relevant term over the effect of the breach in relation to the loss claimed in substance. An attempt to overcome some of the harsh consequences of this technical and strict approach was made by s 11 of the Insurance Act 2015 (UK) (the IA 2015). The wording of s 11, however, is by no means immune from controversies. The starting point of examining the section is to determine whether the relevant insurance contract term defines the risk as a whole. Very limited guidance, however, as to which terms fall within this category is provided by either the IA 2015 or the documents published in the preparatory stages of the Insurance Bill 2014 (UK). The Law Commissions expressly left this matter to be determined by the courts. This paper will seek to clarify the wording of s 11 in terms of ascertaining which terms, when breached, will not instantly provide a pre-determined remedy because of their form, but will rather require an investigation of the substantive effect of their breach in relation to the insured’s loss.

Interviewer effects on patterns of nonresponse: Evaluating the impact on the reasons for contraceptive nonuse in the Indonesia and the Philippines DHS

Background: Much social science research is reliant on generating data through questionnaires and interviews. Understanding the processes by which this data is generated is therefore vital for ensuring validity of scientific results. Interviewers, as a primary means of collecting responses, are one mode through which the generation of data can be affected. Methods: This paper uses the reason for contraceptive non-use module of the Indonesian DHS to examine the effect of differential effects of interviewers on response patterns. A cross-classified multilevel model is used to examine the effect of question order on the probability of providing a positive response. Results: The probability of providing a response declines across the module, an effect which is robust to the introduction of controls. We are able to partition the effect of this decline into respondent and interviewer effects by cross-classified residuals in the multilevel model. We find that although significant, the substantive effect of interviewers on the response profile is small and the majority of variation is accounted for by interviewee-level variation. Conclusions: While data collection via interviewers seems to be a reliable mechanism within the DHS, care should be taken to minimise respondent burden to ensure valid responses. Contribution: This submission confirms the high quality of DHS interviewing practices, while finding evidence of some systematic effects of data collection on responses.

The Civic Voluntarism of “Custodial Citizens”: Involuntary Criminal Justice Contact, Associational Life, and Political Participation

A growing body of research explores the influence of involuntary criminal justice contact on political participation, demonstrating that all types of contact weaken political participation. We posit, however, that personal connections to civil society organizations (CSOs) moderate the negative effects of involuntary criminal justice contact on political participation, particularly political activism beyond registering to vote and voting. We test this proposition with individual-level and aggregate-level data from metropolitan and municipal Chicago. Our findings confirm a paradox of participation by custodial citizens. One, we demonstrate positive, statistically significant, and substantive effects of personal connections to CSOs onnonvoting political participationby custodial citizens. Two, the negative effects of involuntary criminal justice contact onvoting participationamong individuals and communities may endure, despite personal connections to CSOs, even in a state where the franchise is restored immediately after incarceration. Our study suggests that an associational account of political participation deepens our understanding of the political behavior of custodial citizens and their communities in the age of mass incarceration.

Lack of a substantive effect of insurance and the national US payment system on the relative distribution of surgical cases among hospitals in the State of Iowa: A retrospective, observational, cohort study

Study objectiveOur aim was to quantify the extent to which the distribution of patients among payers and changes to the payers' policies has influenced the market of surgery among hospitals in a relatively rural state. DesignRetrospective cohort study. SettingIowa Hospital Association data analyzed were from 2007 through 2016 for the N = 121 hospitals with at least one case performed that included a major therapeutic procedure. MeasurementsWe used five categories of payer (e.g., Medicare), five categories of patient age (e.g., 18 to 64 years), and three categories of patient residence location (e.g., neither from the county of the hospital nor from a county contiguous to the county of the hospital). Main resultsSorting hospitals in descending sequence of numbers of surgical cases, depending on year, the top 10% of hospitals performed 58.4% to 59.2% of the cases. Increases in numbers of cases among patients with commercial insurance increased the heterogeneity among hospitals in numbers of surgical cases (P < 0.0001). However, the magnitude of the effect was very small, with an estimated relative marginal effect on the overall Gini index of only 0.9% ± 0.2% (SE). Increases in numbers of cases of patients with Medicare insurance reduced the heterogeneity in numbers of cases among hospitals (P < 0.0001), but also with very small magnitude (−0.9% ± 0.2%). In contrast, factors encouraging patient travel contributed to larger hospitals becoming larger, and smaller hospitals becoming smaller (3.9% ± 0.7%, P < 0.0001). ConclusionsWe found the absence of a substantive effect of insurance and national US payment systems on the relative distribution of surgical cases among hospitals. Anesthesia groups should focus on payer and payment reform in terms of their effects on payment rates (e.g., average payment per relative value guide unit), not on their potential effects on hospital caseloads.

Invisible Coattails: Presidential Approval and Gubernatorial Elections, 1994–2014

Abstract Hoping to insulate their contests from national politics, thirty-six states hold their gubernatorial elections in national midterm election years. Many scholars have assessed whether presidential evaluations nevertheless have an effect on these races, though findings have varied. We offer a new approach to examining this question, relying on underutilized state-level presidential approval data preceding 143 gubernatorial races across six national midterm election cycles. Accounting for the effects of state ideology, gubernatorial approval, campaign spending, state economic performance, and incumbency, we report that presidential approval has a positive and significant effect on the performance of the presidential party in gubernatorial races. The substantive effects are modest, though still potentially meaningful. In the primary specification, an additional six points of presidential approval is associated with about one additional point of gubernatorial vote share.

Investigating the substantive effectiveness of Strategic Environmental Assessment of urban planning: Evidence from Italy and Spain

We investigated the substantive effectiveness of Strategic Environmental Assessment (SEA) of urban planning in Italy and Spain, by looking at the changes made to the original plan as a result of the SEA process. The Italian and Spanish SEA legislations establish an SEA Authority, different from the one that elaborates the plan and the Environmental Report. This authority is in charge of supervising the SEA process and issuing a final statement containing directions and prescriptions on environmental issues to be implemented in the plan as a prerequisite for its approval. After having reviewed a sample of SEA in these two countries, we found that in the great majority of cases the SEA authority required some changes, despite the fact that the plans had undergone an environmental assessment. Results also indicate that the legal arrangements, and in particular the level of independence of the SEA authority (which in Italy and Spain is determined at the regional level), affect the quality and quantity of requested changes. In regions where the SEA Authority is established at a higher level in the planning hierarchy, more substantial changes tended to be required, including more mitigation and compensation measures. On the contrary, in regions where a subsidiary approach is in place, i.e. the SEA authority is established within the same municipality that elaborates the plan, less substantial modifications are more often required. We conclude that in the Spanish and Italian contexts a more effective SEA, in terms of environmental performance of urban plans, is supported by institutional arrangements that provide for an SEA Authority clearly separated and fully independent from the planning Authority.

The Effect of the Conservation Reserve Program on Rural Economies: Deriving a Statistical Verdict from a Null Finding

AbstractThis article suggests two methods for deriving a statistical verdict from a null finding, allowing economists to more confidently conclude when “not significant” can be interpreted as “no substantive effect.” The proposed methodologies can be extended to a variety of empirical contexts where size and power matter. The example used to demonstrate the methods is the Economic Research Service's 2004 Report to Congress that was charged with statistically identifying any unintended negative employment consequences of the Conservation Reserve Program (CRP). The report failed to identify a statistically significant negative long‐term effect of the CRP on employment growth, but the authors correctly cautioned that the verdict of “no negative employment effect” was only valid if the econometric test was statistically powerful. We replicate the 2004 analysis and use new methods of statistical inference to resolve the two critical deficiencies that preclude estimation of statistical power: (a) positing a compelling effect size, and (b) providing an estimate of the variability of an unobserved alternative distribution using simulation methods. We conclude that the test used in the report had high power for detecting employment effects of ‐1% or lower resulting from the CRP, equivalent to job losses reducing a conservative estimate of environmental benefits by one‐third.

Careerists Versus Coal-Miners: Welfare Reforms and the Substantive Representation of Social Groups in the British Labour Party

Many parties have seen declines in working-class legislators and increases in professional career politicians. I argue that career politicians are more likely to adopt policies for strategic political reasons, whereas working-class politicians are more likely to represent the interests of working-class voters. Changes in the representation of these occupational groups matter substantively whenever legislators’ strategic concerns contradict the interests of working-class voters. Welfare reforms adopted in the 1990s and 2000s by the British Labour Party exhibit this divergence. The two types of politicians held very different policy positions, which I measure using a scaling method applied to all speeches made about welfare in the House of Commons from 1987 to 2007. The results carry over to voting behavior and are robust to alternative explanations, including other characteristics of both MPs and their voters. The changing representation of occupational groups has therefore had substantive policy effects, lowering the political influence of working-class voters.

Parental absence, remittances and educational investment in children left behind: Evidence from Nepal

AbstractThis paper utilizes the third wave of the Nepal Living Standards Survey to assess the causal impact of parental absence and remittances on the educational investment in children left behind. Unlike previous studies, we separately identify parental absence and remittances, with careful consideration of self‐selection into migration and endogeneity of remittances. Using a two‐step estimation strategy, we show that parental absence has a substantive disruptive effect on education of children left behind, while remittances have a positive effect. In addition, we show that non‐parental absence has no effect on education. Further, we provide supporting evidence about the channels to disruption. Finally, we show some heterogeneity results by the child’s gender and education status of the mother. The results by child’s gender confirm that remittances relax the liquidity constraints of households by investing in education of the girls. Further, the results by education status of the mother provide evidence that an educated mother can play a role in neutralizing or mitigating the negative effects of parental absence.

Audience Costs and the Dynamics of War and Peace

AbstractWe estimate audience costs and examine their substantive effects on the evolution of interstate disputes by using an infinitely repeated and dynamic game of crisis escalation. Unlike past efforts, our approach estimates country‐specific audience cost parameters without relying on proxy variables, such as democracy measures. Contrary to intuition, increases in a country's audience costs encourage it to initiate disputes in equilibrium because the costs serve as a commitment device during the subsequent crisis, incentivizing the country to stand firm and coercing its opponent to back down. Nonetheless, the results demonstrate that larger audience costs would result in more peace worldwide, as they also discourage potential opponents from initiating disputes. Beyond regime type, we find that a free press, provisions for executive appointment or removal, and historical rivalries are also important determinants of audience costs.

The Effect of the Conservation Reserve Program on Rural Economies: Deriving a Statistical Verdict from a Null Finding

This article suggests two methods for deriving a statistical verdict from a null finding,allowing economists to more confidently conclude when ?not can in fact be interpreted as ?no substantive effect. The proposed methodology can be extended to a variety of empirical contexts where size and power matter. The example used to demonstrate the method is the Economic Research Service's 2004 Report to Congress that was charged with statistically identifying any unintended negative employment consequences of the Conservation Reserve Program (the Program). The report failed to identify a statistically significant negative long-term of the Program on employment growth, but the authors correctly cautioned that the verdict of ?no negative employment effect was only valid if the econometric test was statistically powerful. We replicate the 2004 analysis and use new methods of statistical inference to resolve the two critical deficiencies that preclude estimation of statistical power by economists: 1) positing a compelling size, and 2) providing an estimate of the variability of an unobserved alternative distribution using simulation methods. We conclude that the test used in the report had high power for detecting employment effects of -1 percent or lower resulting from the Program, equivalent to job losses reducing a conservative estimate of environmental benefits by a third.

Multidimensional incongruence and vote switching in Europe

Does ideological incongruence hurt parties in elections? Research on the representational relationship between parties and voters suggests that ideological congruence can boost a party’s electoral prospects. However, while the mechanism is at the individual-level, most of the literature focuses on the party-level. In this article, we develop a set of hypotheses based on a multi-issue conception of party-voter congruence at the individual-level, and examine the electoral consequences of these varying congruence levels in the 2014 European Parliament elections. Consistent with our expectations, comparative analysis finds that ideological and issue-specific incongruence is a significant factor in voting behavior in the European Parliament elections. Although the substantive effects of incongruence are understandably small compared to partisanship, government, or EU performance evaluations, party-voter disagreement consistently matters, and voters’ issue salience is an important moderator of the impact of incongruence on vote choice.

Mosque Involvement and Political Engagement in the United States

AbstractConfronted by a number of home-grown Islamic terrorist attacks, many Americans incorrectly assume that Muslim religiosity correlates with anti-American values and that the American mosque is the center of radical socialization efforts. This paper examines the nature of the relationship between mosque involvement and political engagement. It finds that mosque attendance is positively associated with political engagement only when the attendance engages congregants in ways beyond religious ritual. Attending mosque to pray does not significantly impact political identities or engagement like following politics, registering to vote, voting, or party membership, while participation in other social or religious activities at a mosque is associated with an increased probability of engagement. These results suggest that not all mosque involvement is equally beneficial for promoting political engagement and that religious participation must proactively engage with the social lives of the congregants to have a substantive political effect.

Global Epidemiology, Prevention, and Management of Hepatocellular Carcinoma.

The incidence rate of hepatocellular carcinoma (HCC) is rising. It is one of the most common cancers worldwide and accounts for substantial morbidity and mortality. Chronic hepatitis B virus (HBV) infection, chronic hepatitis C virus (HCV) infection, and nonalcoholic fatty liver disease (NAFLD) are the most important etiologies of HCC, and effective screening and management strategies are crucial to reduce the HCC risk. For HBV, which accounts for the majority of HCC cases, most infections were acquired via perinatal and early horizontal transmission. Universal vaccination of newborns has led to a decline in HCC incidence compared with the pre-vaccination era. Effective antiviral therapies with nucleos(t)ide analogues or pegylated interferon reduced the incidence of HCC. For HCV, the emergence of effective direct-acting antiviral (DAA) agents has substantially improved cure rates; therefore all patients with HCV should be considered for DAA treatment. The most important obstacle in eliminating HCV is access to therapy. For NAFLD, the global incidence is increasing rapidly, thus its impact on HCC incidence may be explosive. Progression to HCC in NAFLD happens particularly in those with nonalcoholic steatohepatitis (NASH) and exacerbated by metabolic syndrome, or PNPLA3 gene polymorphism. Lifestyle changes are imperative while drug therapy has yet to demonstrate substantive protective effects on HCC prevention. For management of HCC, early diagnosis via imaging surveillance among persons with HCC risk factors remains the most important strategy to identify early-stage disease appropriate for resection or transplantation.