The Messages Replication Factor: Methods Tailored to Messages as Objects of Study

1994 ◽  
Vol 71 (4) ◽  
pp. 984-996
Author(s):  
Sally Jackson ◽  
Daniel J. O'Keefe ◽  
Dale E. Brashers
Keyword(s):  
Statistical Analysis ◽  
Random Effects ◽  
Fixed Effects ◽  
Communication Research ◽  
Concrete Material ◽  
Replication Factor ◽  
Treatment Comparisons ◽  
Replication Factors ◽  
The Relationship

In research on effects of message variables, it is generally necessary to examine responses to actual messages that represent, embody, or instantiate the values of the variable of interest. Researchers have lately become attentive to problems of confounding in the use of individual concrete messages to represent abstract theoretical contrasts, and replicated treatment comparisons are increasingly common in communication research. How to treat the replications factor in the statistical analysis remains controversial. Whether to treat replication factors as fixed or as random hinges on what is assumed about the relationship between abstract treatment contrasts and their concrete material implementations. We argue that reflection on this relationship justifies a general policy of treating replications as random. Two circumstances in which fixed-effects analyses might seem attractive (the case of matched-message designs and the case of experimental manipulations occurring outside of messages) are considered, but it is concluded that these situations also require random-effects analyses.

scholarly journals Association of bisphenol A with puberty timing: a meta-analysis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hui Meng ◽  
Yunping Zhou ◽  
Yunxia Jiang
Keyword(s):  
Bisphenol A ◽  
Confidence Intervals ◽  
Random Effects ◽  
Strong Correlation ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Random Effects Models ◽  
Study Heterogeneity ◽  
The Relationship ◽  
Prevalence Ratios

AbstractObjectivesThe results of existing studies on bisphenol A (BPA) and puberty timing did not reach a consensus. Thereby we performed this meta-analytic study to explore the association between BPA exposure in urine and puberty timing.MethodsMeta-analysis of the pooled odds ratios (OR), prevalence ratios (PR) or hazards ratios (HR) with 95% confidence intervals (CI) were calculated and estimated using fixed-effects or random-effects models based on between-study heterogeneity.ResultsA total of 10 studies involving 5621 subjects were finally included. The meta-analysis showed that BPA exposure was weakly associated with thelarche (PR: 0.96, 95% CI: 0.93–0.99), while no association was found between BPA exposure and menarche (HR: 0.99, 95% CI: 0.89–1.12; OR: 1.02, 95% CI: 0.73–1.43), and pubarche (OR: 1.00, 95% CI: 0.79–1.26; PR: 1.00, 95% CI: 0.95–1.05).ConclusionsThere was no strong correlation between BPA exposure and puberty timing. Further studies with large sample sizes are needed to verify the relationship between BPA and puberty timing.

The relationship between migraine and infant colic: A systematic review and meta-analysis

Cephalalgia ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Amy A Gelfand ◽  
Peter J Goadsby ◽  
I Elaine Allen
Keyword(s):  
Systematic Review ◽  
Random Effects ◽  
Odds Ratio ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Random Effects Model ◽  
Fixed Effects Model ◽  
Primary Analysis ◽  
Infant Colic ◽  
The Relationship

Context Infant colic is a common and distressing disorder of early infancy. Its etiology is unknown, making treatment challenging. Several articles have suggested a link to migraine. Objective The objective of this article was to perform a systematic review and, if appropriate, a meta-analysis of the studies on the relationship between infant colic and migraine. Data sources Studies were identified by searching PubMed and ScienceDirect and by hand-searching references and conference proceedings. Study selection For the primary analysis, studies specifically designed to measure the association between colic and migraine were included. For the secondary analysis, studies that collected data on colic and migraine but were designed for another primary research question were also included. Data extraction Data were abstracted from the original studies, through communication with study authors, or both. Two authors independently abstracted data. Main outcomes and measures The main outcome measure was the association between infant colic and migraine using both a fixed-effects model and a more conservative random-effects model. Results Three studies were included in the primary analysis; the odds ratio for the association between migraine and infant colic was 6.5 (4.6–8.9, p < 0.001) for the fixed-effects model and 5.6 (3.3–9.5, p = 0.004) for the random-effects model. In a sensitivity analysis wherein the study with the largest effect size was removed, the odds ratio was 3.6 (95% CI 1.7–7.6, p = 0.001) for both the fixed-effects model and random-effects model. Conclusions In this meta-analysis, infant colic was associated with increased odds of migraine. If infant colic is a migrainous disorder, this would have important implications for treatment. The main limitation of this meta-analysis was the relatively small number of studies included.

scholarly journals P075 Travel or cheers? Examining the drivers and mechanisms of home court advantage in the 2020/2021 NBA regular season

2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A45-A45
Author(s):  
J Leota ◽  
D Hoffman ◽  
L Mascaro ◽  
M Czeisler ◽  
K Nash ◽  
...  
Keyword(s):  
Random Effects ◽  
Mixed Models ◽  
Fixed Effects ◽  
Natural Experiment ◽  
National Basketball Association ◽  
Home Team ◽  
The Road ◽  
On The Road ◽  
The Impact ◽  
The Relationship

Abstract Introduction Home court advantage (HCA) in the National Basketball Association (NBA) is well-documented, yet the co-occurring drivers responsible for this advantage have proven difficult to examine in isolation. The Coronavirus disease (COVID-19) pandemic resulted in the elimination of crowds in ~50% of games during the 2020/2021 NBA season, whereas travel remained unchanged. Using this ‘natural experiment’, we investigated the impact of crowds and travel-related sleep and circadian disruption on NBA HCA. Methods 1080 games from the 2020/2021 NBA regular season were analyzed using mixed models (fixed effects: crowds, travel; random effects: team, opponent). Results In games with crowds, home teams won 58.65% of the time and outrebounded (M=2.28) and outscored (M=2.18) their opponents. In games without crowds, home teams won significantly less (50.60%, p = .01) and were outrebounded (M=-0.41, p &lt; .001) and outscored (M=-0.13, p &lt; .05) by their opponents. Further, the increase in home rebound margin fully mediated the relationship between crowds and home points margin (p &lt; .001). No significant sleep or circadian effects were observed. Discussion Taken together, these results suggest that HCA in the 2020/2021 NBA season was predominately driven by the presence of crowds and their influence on the effort exerted by the home team to rebound the ball. Moreover, we speculate that the strict NBA COVID-19 policies may have mitigated the travel-related sleep and circadian effects on the road team. These findings are of considerable significance to a domain wherein marginal gains can have immense competitive, financial, and even historical consequences.

scholarly journals Metaanalysis of the relationship between violent video game play and physical aggression over time

2018 ◽  
Vol 115 (40) ◽  
pp. 9882-9888 ◽  
Author(s):  
Anna T. Prescott ◽  
James D. Sargent ◽  
Jay G. Hull
Keyword(s):  
Random Effects ◽  
Video Game ◽  
Physical Aggression ◽  
Fixed Effects ◽  
Time Lags ◽  
Random Effects Models ◽  
Video Game Play ◽  
Game Violence ◽  
The Relationship ◽  
Significant Moderator

To clarify and quantify the influence of video game violence (VGV) on aggressive behavior, we conducted a metaanalysis of all prospective studies to date that assessed the relation between exposure to VGV and subsequent overt physical aggression. The search strategy identified 24 studies with over 17,000 participants and time lags ranging from 3 months to 4 years. The samples comprised various nationalities and ethnicities with mean ages from 9 to 19 years. For each study we obtained the standardized regression coefficient for the prospective effect of VGV on subsequent aggression, controlling for baseline aggression. VGV was related to aggression using both fixed [β = 0.113, 95% CI = (0.098, 0.128)] and random effects models [β = 0.106 (0.078, 0.134)]. When all available covariates were included, the size of the effect remained significant for both models [β = 0.080 (0.065, 0.094) and β = 0.078 (0.053, 0.102), respectively]. No evidence of publication bias was found. Ethnicity was a statistically significant moderator for the fixed-effects models (P≤ 0.011) but not for the random-effects models. Stratified analyses indicated the effect was largest among Whites, intermediate among Asians, and nonsignificant among Hispanics. Discussion focuses on the implications of such findings for current debates regarding the effects of violent video games on physical aggression.

Meta Analysis of Study Habits and Academic Achievement

2021 ◽  
Vol 8 (4) ◽  
pp. 139-145
Author(s):  
M Elango ◽  
G Manimozhi
Keyword(s):  
College Students ◽  
Academic Achievement ◽  
Random Effects ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Study Habits ◽  
Random Effects Model ◽  
Inclusion Criteria ◽  
Analytical Review ◽  
The Relationship

A Meta analytical review investigated the study habits and academic achievement of school and college students. In this study the sample consists of twenty seven reviews based on study habits and academic achievement/ performance. The sample of the review based on inclusion criteria such as study habits and academic achievement. The review was collected by following details such as title of the study, Name of the author, Sample of the study, correlation Value and findings of the study. The Meta analysis is on the relationship between study habits and academic achievement. The main aim of the study is to find the fixed effects, random effects model values, Heterogeneity and forest plots. A Meta analysis of research paper was formed the conclusion.

scholarly journals PSIII-11 Semen quality effect on conception rate among three purebred swine lines

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 163-163
Author(s):  
Giselle Kruse ◽  
Cailtyn Bruns
Keyword(s):  
Logistic Regression ◽  
Random Effects ◽  
Odds Ratio ◽  
Fixed Effects ◽  
Logistic Regression Model ◽  
Semen Quality ◽  
Conception Rate ◽  
Conception Rates ◽  
The Relationship ◽  
Effect Of Age

Abstract The objective of this study was to examine the relationship between semen quality and conception rate. There were 30985 Duroc, 15888 Landrace, and 18198 Yorkshire single sire, purebred mating observations with 880 Duroc, 508 Landrace, and 492 Yorkshire boars represented from March 2011 to July 2018. Data from each breed was analyzed using a logistic regression model with fixed effects of sow parity at time of mating, the number of breeding attempts for the sow, days rest of the boar, and days from collection to insemination, covariates of age at collection, motility, percent abnormal tails, and random effects of contemporary group, boar, and evaluator. For Duroc, increased percent abnormal tails decreased conception rate (odds ratio=0.99, P < 0.05), and more than 9 days rest resulted in lower conception rates compared to less than 5 days rest (odds ratio=0.85, P < 0.05). For all three breeds, inseminations occurring 2 days post-collection tended to result in lower conception rate compared to 1 day post-collection (Duroc, odds ratio=0.94, P < 0.1, Yorkshire, odds ratio=0.87, P < 0.1, Landrace, odds ratio=0.91,P < 0.05); however, for Landrace, inseminations occurring 4 days post collection resulted in higher conception rates compared to 1 day post-collection (odds ratio=1.16, P < 0.05). For Yorkshire, increased motility was associated with higher conception rates (odds ratio=1.02, P < 0.001). The effect of age at collection on conception rate was small, but significant for both Landrace and Duroc resulting in ~1% increase per year of age (P < 0.05). Boar and semen quality effects on conception rate were inconsistent across breeds, suggesting that optimizing conception rates across breeds could be difficult.

scholarly journals The effect of cooperative learning on academic achievement: A meta-analysis on the relationship between the study group size and effect size İşbirlikli öğrenmenin başarıya etkisi: Çalışma grubu ile etki büyüklüğü arasındaki ilişkiye dair bir meta analiz çalışması

2017 ◽  
Vol 14 (1) ◽  
pp. 473 ◽  
Author(s):  
Murat Tuncer ◽  
Melih Dikmen
Keyword(s):  
Cooperative Learning ◽  
Random Effects ◽  
Effect Size ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Study Group ◽  
Random Effects Model ◽  
Learning Groups ◽  
The Relationship

The purpose of this study was to determine the effect of cooperative learning on achievement and the relationship between the study group and effect size by means of meta-analysis. Meta-analysis is the method employed in order to statistically analyze the quantitative data collected in independent and multiple studies carried out on similar topics, and to reach a general judgment regarding the results of these studies.  Certain criteria were used in order to decide which researches would be included in the meta-analysis. Based on these criteria, it was decided to include 6 experimental studies in the meta-analysis. As a result, for the six studies, the effect size calculated within 95 % confidence interval has proved to be .518 based on random effects model. When two studies with the largest learning groups are excluded from the research respectively, firstly this effect size increases to .528, later it is calculated as .817 without any model discrimination. When effect size intervals in literature (≥ 0.5: strong, ≥ 0.3: moderate and  ≥ .01 weak) is taken into consideration, the effect of cooperative learning on achievement has been observed as  “Strong”. In addition to this, contrary to some views in literature, it has been seen that large learning groups have higher standard errors and a bigger effect size has been achieved when such studies have been excluded from the analysis. What is more, even the limitation of fixed effects model has disappeared, and the effect size calculated in fixed effects and random effects model has been balanced.  ÖzetBu araştırmanın amacı, işbirlikli öğrenmenin başarı üzerindeki etkisini ve çalışma grubu ile etki büyüklüğü arasındaki ilişkiyi meta-analiz yöntemiyle belirlemektir. Meta-analiz, benzer konularda yapılmış birbirinden bağımsız ve çok sayıda çalışmadan elde edilmiş sayısal verileri istatistiksel olarak analiz etme ve bu çalışmaların sonuçları hakkında genel bir yargıya varma yöntemidir. Hangi araştırmaların meta-analize dâhil edileceğine yönelik seçimlerin yapılmasında belirli ölçütler kullanılmıştır. Bu ölçütlere dayalı olarak 6 adet deneysel araştırmanın meta-analize dâhil edilmesine karar verilmiştir. Sonuç olarak; altı çalışma için %95 güven aralığında hesaplanan etki büyüklüğü rastgele etkiler modeline göre .518’dir. En büyük çalışma grubuna sahip iki araştırma sırasıyla araştırma dışında tutulduğunda bu etki büyüklüğü önce .528’ e çıkmakta, sonrasında ise model ayrımı olmaksızın .817 olarak hesaplanmaktadır. Alan yazındaki etki büyüklüğü aralıkları (≥ 0.5: güçlü, ≥ 0.3: orta düzey ve ≥ .01 zayıf) dikkate alındığında işbirlikli öğrenmenin başarı üzerindeki etkisi “Güçlü” bir etki olarak gözlenmiştir. Ayrıca alan yazındaki bazı görüşlerin aksine büyük çalışma gruplarının standart hatalarının daha yüksek olduğu, bu araştırmaların analiz dışında tutulması ile daha büyük etki büyüklüklerine ulaşıldığı, hatta sabit etki modelinin sınırlılığının bile ortadan kalktığı, sabit etki ve rastgele etki modelinde hesaplanan etki büyüklüğünün eşitlendiği görülmüştür.

scholarly journals Board of Directors’ Size and Firm Performance: Evidence from Non-Financial French Firms Listed on CAC 40

2020 ◽  
Vol 15 (2) ◽  
pp. 46-61
Author(s):  
Hemza Boussenna
Keyword(s):  
Firm Performance ◽  
Panel Data ◽  
Board Of Directors ◽  
Random Effects ◽  
Fixed Effects ◽  
Optimal Number ◽  
Board Size ◽  
The Relationship ◽  
Positive Effect

AbstractThe study aims to investigate the relationship between board size and firm’s performance for a sample of non-financial French firms listed on the CAC 40 between 2005 and 2017. We estimated the firm’s performance using two types of metrics, the accounting-based measures (ROA and ROE) and the market-based measures (Tobin Q and MTB). By applying the panel data regressions (fixed-effects and random-effects), the findings show that there is a positive effect of board size on firm performance. In addition, our results show that the optimal number of the board size should be between 13 and 17 members in order to achieve good performance for non-financial French firms.

scholarly journals Financial Centres Index and GDP Growth

2016 ◽  
Vol 8 (4) ◽  
pp. 198
Author(s):  
Sinan Esen ◽  
Korhan Gokmenoglu
Keyword(s):  
Random Effects ◽  
Fixed Effects ◽  
Gdp Growth ◽  
Fixed Effects Model ◽  
Financial Centre ◽  
The Relationship

This study investigates the relationship between financial centres index and GDP growth of 20 countries with the world’s largest GDP. In our sample each country is represented by just one financial centre. We tested many models through several panel approaches. Use of a fixed-effects model, fixed-effects (within) regression, random-effects GLS regression, random-effects ML regression, and empirical findings showed that the global financial centres index variable is highly statistically significant, and coefficients obtained from different estimations are very close to each other. Our findings support the idea that financial centres positively affect the GDP growth of countries.

scholarly journals Applied Comparison of Meta-analysis Techniques

10.36469/9848 ◽  
2013 ◽  
Vol 1 (1) ◽  
pp. 14-22
Author(s):  
Li Wang ◽  
Colin Lewis-Beck ◽  
Elyse Fritschel ◽  
Erdem Baser ◽  
Onur Baser
Keyword(s):  
Random Effects ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Fixed Effects Model ◽  
Analysis Techniques ◽  
Level Data ◽  
Study Results ◽  
Meta Regression ◽  
Treatment Comparisons ◽  
Analysis Models

Background: Meta-analysis is an approach that combines findings from similar studies. The aggregation of study level data can provide precise estimates for outcomes of interest, allow for unique treatment comparisons, and explain the differences arising from conflicting study results. Proper meta-analysis includes five basic steps: identify relevant studies; extract summary data from each paper; compute study effect sizes, perform statistical analysis; and interpret and report the results. Objectives: This study aims to review meta-analysis methods and their assumptions, apply various meta-techniques to empirical data, and compare the results from each method. Methods: Three different meta-analysis techniques were applied to a dataset looking at the effects of the bacille Calmette-Guerin (BCG) vaccine on tuberculosis (TB). First, a fixed-effects model was applied; then a random-effects model; and third meta-regression with study-level covariates were added to the model. Overall and stratified results, by geographic latitude were reported. Results: All three techniques showed a statistically significant effects from the vaccination. However, once covariates were added, efficacy diminished. Independent variables, such as the latitude of the location in which the study was performed, appeared to be partially driving the results. Conclusions: Meta-analysis is useful for drawing general conclusions from a variety of studies. However, proper study and model selection are important to ensure the correct interpretation of results. Basic meta-analysis models are fixed-effects, random-effects, and meta-regression.

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