Pub Date : 2018-12-01DOI: 10.22812/JETEM.2018.29.4.003
Daeha Cho, K. Kim
This paper departs from the representative-agent assumption and investigates how optimal monetary policy should be conducted in a two-agent New Keynesian (TANK) model. Relative to a price stability motive that typically appears as policy prescriptions in representative-agent New Keynesian (RANK) models, heterogeneity adds a motive to spread aggregate fluctuations equally across all households. We show that the latter motive hinges on how fiscal transfers are implemented with the business cycle.
{"title":"Redistribution and Optimal Monetary Policy","authors":"Daeha Cho, K. Kim","doi":"10.22812/JETEM.2018.29.4.003","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.4.003","url":null,"abstract":"This paper departs from the representative-agent assumption and investigates how optimal monetary policy should be conducted in a two-agent New Keynesian (TANK) model. Relative to a price stability motive that typically appears as policy prescriptions in representative-agent New Keynesian (RANK) models, heterogeneity adds a motive to spread aggregate fluctuations equally across all households. We show that the latter motive hinges on how fiscal transfers are implemented with the business cycle.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":"61-80"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44756105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.22812/JETEM.2018.29.4.002
Byoung Hoon Seok, Hye Mi You
This paper explores the effect of the progressivity of income taxes on the distribution of income and consumption across households as well as the aggregate output in Korea. Using Korean administrative data on income and tax by income percentile,we find that the post-2012 progressivity of Korean income taxes is double the pre-2012 progressivity. By building a dynamic general equilibrium model with heterogeneous agents, we quantify the long-run effect of the increased progressivity of income taxes on Korean economy. We find that the more progressive income taxes increase the government's tax revenue, while reducing the dispersion in income and consumption across individuals. However, the bottom decile of the income distribution is the only group that experiences a rise in consumption, while the consumption of all other income deciles is reduced. This is attributed to the large decline in the aggregate capital. Faced with the increased tax burden, high income earners reduce their savings, causing the aggregate capital and thereby output to decrease.
{"title":"An Economic Analysis of the Progressivity of Income Taxes Using a Dynamic General Equilibrium Model","authors":"Byoung Hoon Seok, Hye Mi You","doi":"10.22812/JETEM.2018.29.4.002","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.4.002","url":null,"abstract":"This paper explores the effect of the progressivity of income taxes on the distribution of income and consumption across households as well as the aggregate output in Korea. Using Korean administrative data on income and tax by income percentile,we find that the post-2012 progressivity of Korean income taxes is double the pre-2012 progressivity. By building a dynamic general equilibrium model with heterogeneous agents, we quantify the long-run effect of the increased progressivity of income taxes on Korean economy. We find that the more progressive income taxes increase the government's tax revenue, while reducing the dispersion in income and consumption across individuals. However, the bottom decile of the income distribution is the only group that experiences a rise in consumption, while the consumption of all other income deciles is reduced. This is attributed to the large decline in the aggregate capital. Faced with the increased tax burden, high income earners reduce their savings, causing the aggregate capital and thereby output to decrease.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":"16-60"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46481250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.22812/JETEM.2018.29.3.002
Chang Lee, K. Kang, Junghwan Mok
The instability of the financial system is likely to occur when particular types of loans surge rather than all types of loans surge at the same time. A preemptive policy response requires a monitoring system based on forecasts by different loan types. The purpose of this study is to forecast household loans bycategorizingintofourtypes:bankmortgageloan,bankcreditloan,non-bank mortgage loan, and non-bank credit loan. Given the fact that there are numerous determinants and forecasting models for household loans, and that the determinants differ depending on the type of household loans, this study sets out the density forecasting algorithm based on Bayesian Machine Learning. which consists of a variable learning process, a model learning process, and a forecasting combination process. We find bank mortgage loans are largely predicted by the loan rates, the volume of apartments to be moved in, and the number of apartment units to be sold. while the key determinants of bank credit loans are the employmentrateandJeon-sepriceindex.Ontheotherhand,thenon-bankmortgage loans are largely determined by the loan rates and the ratio of apartment sales prices relative to Jeon-se prices. The non-bank credit loans are also influencedbynotonlytheemploymentrateandtheJeon-sepriceindexbutalsostock returns.
{"title":"Determinants of Bank and Non-bank Household Loans and Short- and Long- Horizon Forecast","authors":"Chang Lee, K. Kang, Junghwan Mok","doi":"10.22812/JETEM.2018.29.3.002","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.3.002","url":null,"abstract":"The instability of the financial system is likely to occur when particular types of loans surge rather than all types of loans surge at the same time. A preemptive policy response requires a monitoring system based on forecasts by different loan types. The purpose of this study is to forecast household loans bycategorizingintofourtypes:bankmortgageloan,bankcreditloan,non-bank mortgage loan, and non-bank credit loan. Given the fact that there are numerous determinants and forecasting models for household loans, and that the determinants differ depending on the type of household loans, this study sets out the density forecasting algorithm based on Bayesian Machine Learning. which consists of a variable learning process, a model learning process, and a forecasting combination process. We find bank mortgage loans are largely predicted by the loan rates, the volume of apartments to be moved in, and the number of apartment units to be sold. while the key determinants of bank credit loans are the employmentrateandJeon-sepriceindex.Ontheotherhand,thenon-bankmortgage loans are largely determined by the loan rates and the ratio of apartment sales prices relative to Jeon-se prices. The non-bank credit loans are also influencedbynotonlytheemploymentrateandtheJeon-sepriceindexbutalsostock returns.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":"23-57"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45118334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-01DOI: 10.22812/JETEM.2018.29.2.001
J. Cho, Jin Seok Park, Sang Woo Park
This study examines the mixture hypothesis of conditional geometric distributions using a likelihood ratio (LR) test statistic based on that used for unconditionalgeometricdistributions. Assuch,wederivethenulllimitdistribution of the LR test statistic and examine its power performance. In addition, we examine the interrelationship between the LR test statistics used to test the geometric and exponential mixture hypotheses. We also examine the performance of the LR test statistics under various conditions and confirm the main claims of the study using Monte Carlo simulations.
{"title":"Testing for the Mixture Hypothesis of Conditional Geometric and Exponential Distributions","authors":"J. Cho, Jin Seok Park, Sang Woo Park","doi":"10.22812/JETEM.2018.29.2.001","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.2.001","url":null,"abstract":"This study examines the mixture hypothesis of conditional geometric distributions using a likelihood ratio (LR) test statistic based on that used for unconditionalgeometricdistributions. Assuch,wederivethenulllimitdistribution of the LR test statistic and examine its power performance. In addition, we examine the interrelationship between the LR test statistics used to test the geometric and exponential mixture hypotheses. We also examine the performance of the LR test statistics under various conditions and confirm the main claims of the study using Monte Carlo simulations.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":"1-27"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48425906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-01DOI: 10.22812/JETEM.2018.29.1.003
Soondong Hong, C. Kim
This paper studies the price elasticity of the peak electricity demand of the residential sector in Korea using high frequency data collected by AMR (Automatic Meter Reading) system. The main purpose of this paper is to estimate the price elasticity by allowing the nonlinear relationship between price and temperature in the short-run residential electricity demand curve. Specifically, we consider a Logistic Smooth Transition Regression model with functional coefficients to capture the temperature-dependent price elasticity of residential peak demand in Korea. We show conclusive evidence that the non-economic variables influence the price elasticity of peak residential demand in Korea. Our estimation results show that the price elasticity is dependent upon temperature, and peak demand becomes more sensitive when the weather is very hot or cold.
{"title":"Estimating the Price Elasticity of Peak Residential Demand using High Frequency Data","authors":"Soondong Hong, C. Kim","doi":"10.22812/JETEM.2018.29.1.003","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.1.003","url":null,"abstract":"This paper studies the price elasticity of the peak electricity demand of the residential sector in Korea using high frequency data collected by AMR (Automatic Meter Reading) system. The main purpose of this paper is to estimate the price elasticity by allowing the nonlinear relationship between price and temperature in the short-run residential electricity demand curve. Specifically, we consider a Logistic Smooth Transition Regression model with functional coefficients to capture the temperature-dependent price elasticity of residential peak demand in Korea. We show conclusive evidence that the non-economic variables influence the price elasticity of peak residential demand in Korea. Our estimation results show that the price elasticity is dependent upon temperature, and peak demand becomes more sensitive when the weather is very hot or cold.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43119760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-01DOI: 10.22812/JETEM.2018.29.3.001
Lola Esteban, J. Hernández
This paper analyzes how the use of mass vs. direct advertising can affect the pattern of price and quality competition in a market where two firms compete with vertically differentiated products. We show that, compared to the casewheresellersemployonlymassadvertising,theuseofdatabaseadvertising based on historical sales records improves the competitive position of the lowquality firm, which achieves a larger market share and can obtain higher profits. As a result, the high-quality firm lowers the supply of quality, which decreases thedegreeofproductdifferentiationinthemarketandtriggersstrongpricecompetition,thusdecreasingitsprofitsandincreasingconsumersurplus. Finally,we show that, although database advertising is more cost-efficient than mass advertising, the market distortion in the provision of quality implies that the use of direct advertising can yield a welfare loss.
{"title":"Mass versus Direct Advertising and Product Quality","authors":"Lola Esteban, J. Hernández","doi":"10.22812/JETEM.2018.29.3.001","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.3.001","url":null,"abstract":"This paper analyzes how the use of mass vs. direct advertising can affect the pattern of price and quality competition in a market where two firms compete with vertically differentiated products. We show that, compared to the casewheresellersemployonlymassadvertising,theuseofdatabaseadvertising based on historical sales records improves the competitive position of the lowquality firm, which achieves a larger market share and can obtain higher profits. As a result, the high-quality firm lowers the supply of quality, which decreases thedegreeofproductdifferentiationinthemarketandtriggersstrongpricecompetition,thusdecreasingitsprofitsandincreasingconsumersurplus. Finally,we show that, although database advertising is more cost-efficient than mass advertising, the market distortion in the provision of quality implies that the use of direct advertising can yield a welfare loss.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"14 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68342319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-01DOI: 10.22812/JETEM.2018.29.2.003
Taehyung Kim, Jeong-gun Park
We proposes a new Bayesian MCMC algorithm for dynamic stochastic copula models with dependence parameters as unobserved state variables and presents the performance of the proposed MCMC algorithm through simulations. Our MCMC algorithm draws the state variables with an acceptancerejection Metropolis-Hastings algorithm using the candidate generating probability density function obtained by approximating the probability density function of the observed variables to the normal distribution of the dependence parameter.As an empirical example,weanalyzedthe stochasticcopulamodels for the KOSPI index and the HSCE index (Hang Seng China enterprise index) returnsfromJanuary3,2003toDecember30,2014usingtheproposedalgorithm. The Bayesian inference and model comparison results of the stochastic copula models of Gaussian copula, Student t-copula, Clayton copula, Frank copula, rotated Gumbel copula, and Plackett copula showed that Student t-copula model couldbeselectedasthebestmodel.Thesemodelcomparisonsresultsimplythat even though Gaussian stochastic copula model can capture ��near asymptotic dependence��, there may exist extreme tail dependence that can not be captured by the Gaussian stochastic copula model.
{"title":"Bayesian Inference for Stochastic Copula Models","authors":"Taehyung Kim, Jeong-gun Park","doi":"10.22812/JETEM.2018.29.2.003","DOIUrl":"https://doi.org/10.22812/JETEM.2018.29.2.003","url":null,"abstract":"We proposes a new Bayesian MCMC algorithm for dynamic stochastic copula models with dependence parameters as unobserved state variables and presents the performance of the proposed MCMC algorithm through simulations. Our MCMC algorithm draws the state variables with an acceptancerejection Metropolis-Hastings algorithm using the candidate generating probability density function obtained by approximating the probability density function of the observed variables to the normal distribution of the dependence parameter.As an empirical example,weanalyzedthe stochasticcopulamodels for the KOSPI index and the HSCE index (Hang Seng China enterprise index) returnsfromJanuary3,2003toDecember30,2014usingtheproposedalgorithm. The Bayesian inference and model comparison results of the stochastic copula models of Gaussian copula, Student t-copula, Clayton copula, Frank copula, rotated Gumbel copula, and Plackett copula showed that Student t-copula model couldbeselectedasthebestmodel.Thesemodelcomparisonsresultsimplythat even though Gaussian stochastic copula model can capture ��near asymptotic dependence��, there may exist extreme tail dependence that can not be captured by the Gaussian stochastic copula model.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"29 1","pages":"48-120"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68342306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-01DOI: 10.22812/JETEM.2017.28.3.003
Eui-hwan Park, D. H. Kim, K. Kim
This study tries to build the financial early warning system (EWS) of the individual financial sector such as banks, securities and savings-loans banks by applying the non-parametric signal approach and to establish a new composite EWS. The empirical results show that the financial sector’s EWSs appeared to identify the financial sector’s crisis timely and the new composite EWS seemed to be very similar with the existing EWS. This study suggests that the financial sector EWS is useful for conducting the microprudential policy based on the financial sector’s characteristics and relating to the implementation of the macroprudential policy for financial stability.
{"title":"The Study on the Development of the Financial Sector Early Warning System","authors":"Eui-hwan Park, D. H. Kim, K. Kim","doi":"10.22812/JETEM.2017.28.3.003","DOIUrl":"https://doi.org/10.22812/JETEM.2017.28.3.003","url":null,"abstract":"This study tries to build the financial early warning system (EWS) of the individual financial sector such as banks, securities and savings-loans banks by applying the non-parametric signal approach and to establish a new composite EWS. The empirical results show that the financial sector’s EWSs appeared to identify the financial sector’s crisis timely and the new composite EWS seemed to be very similar with the existing EWS. This study suggests that the financial sector EWS is useful for conducting the microprudential policy based on the financial sector’s characteristics and relating to the implementation of the macroprudential policy for financial stability.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"28 1","pages":"36-67"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45195404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22812/JETEM.2017.28.2.002
D. Yang, Yongseung Jung
We empirically estimate the effects of expansionary fiscal policy in Korea to analyze the impacts of the fiscal policy with different exchange rate regime. First, we empirically estimate the Structural VAR to identify the transmission mechanism of major macroeconomic variables from government expenditure shocks in Korea. The government expenditure shocks increase consumption, investment, and GDP. At the same time net exports decrease and foreign exchange rates depreciate in the long run. Second, we set up a small open economy model with financial frictions and discuss the role of financial market frictions in generating a multiplier of government expenditure under PEG and flexible exchange regime. Extended the existing literature on fiscal policy by introducing limited asset market participation and external finance a la Bernanke et al. (1999) into the model. Shown that the multiplier can be larger than one under pegged exchange rate regime, while is smaller than one under flexible exchange rate regime.
我们实证估计了韩国扩张性财政政策的效果，以分析不同汇率制度下财政政策的影响。首先，我们实证估计了结构VAR，以确定韩国政府支出冲击对主要宏观经济变量的传导机制。政府支出冲击增加了消费、投资和GDP。与此同时，从长远来看，净出口减少，外汇汇率贬值。其次，我们建立了一个具有金融摩擦的小型开放经济模型，并讨论了在PEG和灵活汇率制度下，金融市场摩擦在产生政府支出乘数中的作用。通过引入有限的资产市场参与和外部融资，扩展了现有的财政政策文献a la Bernanke等人（1999）到模型中。研究表明，在钉住汇率制度下，乘数可以大于1，而在灵活汇率制度下则小于1。
{"title":"Reexamination of Fiscal Policy in a Small Open Economy: The Case of Korea","authors":"D. Yang, Yongseung Jung","doi":"10.22812/JETEM.2017.28.2.002","DOIUrl":"https://doi.org/10.22812/JETEM.2017.28.2.002","url":null,"abstract":"We empirically estimate the effects of expansionary fiscal policy in Korea to analyze the impacts of the fiscal policy with different exchange rate regime. First, we empirically estimate the Structural VAR to identify the transmission mechanism of major macroeconomic variables from government expenditure shocks in Korea. The government expenditure shocks increase consumption, investment, and GDP. At the same time net exports decrease and foreign exchange rates depreciate in the long run. Second, we set up a small open economy model with financial frictions and discuss the role of financial market frictions in generating a multiplier of government expenditure under PEG and flexible exchange regime. Extended the existing literature on fiscal policy by introducing limited asset market participation and external finance a la Bernanke et al. (1999) into the model. Shown that the multiplier can be larger than one under pegged exchange rate regime, while is smaller than one under flexible exchange rate regime.","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"28 1","pages":"29-54"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44344932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marie Baudard, Amélie Yavchitz, Philippe Ravaud, Elodie Perrodeau, Isabelle Boutron
Objective To evaluate the impact of searching clinical trial registries in systematic reviews.Design Methodological systematic review and reanalyses of meta-analyses.Data sources Medline was searched to identify systematic reviews of randomised controlled trials (RCTs) assessing pharmaceutical treatments published between June 2014 and January 2015. For all systematic reviews that did not report a trial registry search but reported the information to perform it, the World Health Organization International Trials Registry Platform (WHO ICTRP search portal) was searched for completed or terminated RCTs not originally included in the systematic review.Data extraction For each systematic review, two researchers independently extracted the outcomes analysed, the number of patients included, and the treatment effect estimated. For each RCT identified, two researchers independently determined whether the results were available (ie, posted, published, or available on the sponsor website) and extracted the data. When additional data were retrieved, we reanalysed meta-analyses and calculated the weight of the additional RCTs and the change in summary statistics by comparison with the original meta-analysis.Results Among 223 selected systematic reviews, 116 (52%) did not report a search of trial registries; 21 of these did not report the information to perform the search (key words, search date). A search was performed for 95 systematic reviews; for 54 (57%), no additional RCTs were found and for 41 (43%) 122 additional RCTs were identified. The search allowed for increasing the number of patients by more than 10% in 19 systematic reviews, 20% in 10, 30% in seven, and 50% in four. Moreover, 63 RCTs had results available; the results for 45 could be included in a meta-analysis. 14 systematic reviews including 45 RCTs were reanalysed. The weight of the additional RCTs in the recalculated meta-analyses ranged from 0% to 58% and was greater than 10% in five of 14 systematic reviews, 20% in three, and 50% in one. The change in summary statistics ranged from 0% to 29% and was greater than 10% for five of 14 systematic reviews and greater than 20% for two. However, none of the changes to summary effect estimates led to a qualitative change in the interpretation of the results once the new trials were added.Conclusions Trial registries are an important source for identifying additional RCTs. The additional number of RCTs and patients included if a search were performed varied across systematic reviews.
{"title":"Impact of searching clinical trial registries in systematic reviews of pharmaceutical treatments: methodological systematic review and reanalysis of meta-analyses.","authors":"Marie Baudard, Amélie Yavchitz, Philippe Ravaud, Elodie Perrodeau, Isabelle Boutron","doi":"10.1136/bmj.j448","DOIUrl":"10.1136/bmj.j448","url":null,"abstract":"<p><p><b>Objective</b> To evaluate the impact of searching clinical trial registries in systematic reviews.<b>Design</b> Methodological systematic review and reanalyses of meta-analyses.<b>Data sources</b> Medline was searched to identify systematic reviews of randomised controlled trials (RCTs) assessing pharmaceutical treatments published between June 2014 and January 2015. For all systematic reviews that did not report a trial registry search but reported the information to perform it, the World Health Organization International Trials Registry Platform (WHO ICTRP search portal) was searched for completed or terminated RCTs not originally included in the systematic review.<b>Data extraction</b> For each systematic review, two researchers independently extracted the outcomes analysed, the number of patients included, and the treatment effect estimated. For each RCT identified, two researchers independently determined whether the results were available (ie, posted, published, or available on the sponsor website) and extracted the data. When additional data were retrieved, we reanalysed meta-analyses and calculated the weight of the additional RCTs and the change in summary statistics by comparison with the original meta-analysis.<b>Results</b> Among 223 selected systematic reviews, 116 (52%) did not report a search of trial registries; 21 of these did not report the information to perform the search (key words, search date). A search was performed for 95 systematic reviews; for 54 (57%), no additional RCTs were found and for 41 (43%) 122 additional RCTs were identified. The search allowed for increasing the number of patients by more than 10% in 19 systematic reviews, 20% in 10, 30% in seven, and 50% in four. Moreover, 63 RCTs had results available; the results for 45 could be included in a meta-analysis. 14 systematic reviews including 45 RCTs were reanalysed. The weight of the additional RCTs in the recalculated meta-analyses ranged from 0% to 58% and was greater than 10% in five of 14 systematic reviews, 20% in three, and 50% in one. The change in summary statistics ranged from 0% to 29% and was greater than 10% for five of 14 systematic reviews and greater than 20% for two. However, none of the changes to summary effect estimates led to a qualitative change in the interpretation of the results once the new trials were added.<b>Conclusions</b> Trial registries are an important source for identifying additional RCTs. The additional number of RCTs and patients included if a search were performed varied across systematic reviews.</p>","PeriodicalId":39995,"journal":{"name":"Journal of Economic Theory and Econometrics","volume":"26 1","pages":"j448"},"PeriodicalIF":0.0,"publicationDate":"2017-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5421496/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90323378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：