The support staff are always helpful and respond quickly when questions arise. It will direct you to useful resources provided by ccace researchers and external bodies. Students are able to return to our computer lab to complete a meta analysis assignment independently after an initial faculty demonstration session. Comprehensive meta analysis cma is essential software for the meta analyst. Metal, including source code, documentation, examples, and. Meta analysis in excel metaxl is a tool for meta analysis in microsoft excel. The glucose data this example examines evidence for association between fasting glucose levels and genetic markers in the g6pc2 chr. Jasp is a free, opensource program used to perform statistical analysis tests by using r packages. Metal can combine either a test statistics and standard errors or b pvalues across studies taking sample size and direction of effect into account. Does the meta analysis include any appropriate relevant studies that may have had negative outcomes. Nov 16, 2010 the purpose of this article is to provide higher education researchers with an illustrative example of meta analysis utilizing hierarchical linear modeling hlm. Conceptually, a meta analysis uses a statistical approach to combine the results from multiple studies in an effort to increase power over individual studies, improve estimates of the size of the effect andor to resolve uncertainty when reports disagree. Lets use metal to run a fixedeffect metaanalysis weighted by sample number fore each study.
To enable correction for sample overlap in your sample size weighted metaanalysis, use. The software facilitates application of complex concepts with real data, helping students see the power of the meta analysis process. This brief tutorial should help you with the first steps in r. Metal is a tool for meta analysis genomewide association scans. In this practical we will run a gwa metaanalysis using metal. The gwama genomewide association metaanalysis software has been.
We, and others, have used metal for performing metaanalysis of gwas to identify loci. Could anyone suggest a free software for meta analysis. If enabled, metal checks if chromosome and position of a variant match across studies. Running meta analysis in r using the metafor package. Metaanalysis method there are three different metaanalysis methods available controlled by the method optionmethod 1. Oct 09, 2015 while the worked example is the analysis of a correlational dataset, the general meta analytic process described in this paper is applicable for all types of effect sizes. It extends excel with several functions for input and output of meta analysis data, and a menu that offers access to output both in table and graphical format, options, examples, and this user guide, among other things. Pdf metal provides a computationally efficient tool for metaanalysis of. These nine steps are in general applicable to all metaanalyses. It explains the background to these methodologies, what is involved, and how to get started, keep going, and finish. Metal provides a computationally efficient tool for metaanalysis of genomewide association scans, which is a commonly used approach for improving power complex traits gene mapping studies. Software with source files, documentation and example data files are freely. On the medical bundle tab in the analyses group, click meta analysis and meta regression to display the meta analysis and meta regression dialog. If available studies are too few or too different a metaanalysis may not be appropriate.
Glass, 1976, p3 metaanalysis techniques are needed because only. This article demonstrates the stepbystep process of meta analysis using a recentlypublished study examining the effects of curricular and cocurricular diversity activities on racial bias in college students as an example denson. Metal analysis is a convenient alternative to a direct analysis of merged data from multiple studies. Meta analysis is a statistical technique, or set of statistical techniques, for summarising the results of several studies into a single estimate. In a few guided examples, we are loading some data, calculating effect sizes and conducting a meta analysis of a fictional data set. What is a metaanalysis in 1976, glass coined the term metaanalysis metaanalysis refers to the analysis of analyses the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings. Complex analyses can be conducted easily using this intuitive software. The cran meta analysis task view is exceptionally wellorganized listing r. Metaanalysis of genome wide association studies angus 6. Since 1980 we have supplied products and services to chemical processing, water treating, and petroleum industries around the world. A meta analysis is a statistical overview of the results from one or more systematic. An exhaustive search of the literature will require more than r. The metal software is designed to facilitate metaanalysis of large datasets such as several whole genome scans in a convenient, rapid and memory efficient manner. Brief overview of methods and general hints description r package meta is a userfriendly general package providing standard methods for meta analysis.
Jul 17, 2014 however, r is the natural platform for meta analysis both because of the myriad possibilities for statistical analyses that are not generally available through the specialized software, and because of the many packages devoted to various aspects of meta analysis. The extracted data depends on the research question, but it may include information such as sample size, patient characteristics, length of study, and a statistical measure, such as confidence interval, odds ratio, risks ratio, mean difference, or hazard ratio. Use the links below to jump to the meta analysis topic you would like to examine. The metal software is designed to facilitate metaanalysis of large datasets such as several whole genome scans in a convenient, rapid and memory efficient. This tutorial walks you through the basic concepts. The program allows you to enter the raw measures and already calculated effect sizes. It has been around for more than 10 years and has been used in hundreds of analyses and publications.
The metaanalysis function of jasp is based on the aforementioned metafor r package. I wish to test the potential association between candidate gene polymorphism and specific disease risk in different populations. I wish to test the potential association between candidate gene polymorphism and specific disease risk in. Metal is a tool for metaanalysis genomewide association scans. For example, you can trying issuing the help command, to which metal. Metal meta analysis helper center for statistical genetics. Now i have genotyped one snp in this sample and calculated the p value for the allelic. By default, metal combined pvalues across studies sample size, direction of effect. An example of a network analysis would be the following. Correction for sample overlap in sample size weighted metaanalysis. Many people find that it easiest to learn by example. I was able to run a metaanalysis in reasonable time.
Provides a computationally efficient tool for metaanalysis of genomewide. The following is an example of a meta analysis conducted in the medical bundle. Nine steps to meta analyses we recommend in general the following nine steps of meta analysis. Running metaanalysis in r using the metafor package. This website includes a download page, brief documentation in our wiki and a registration page. So, if reading through our extensive documentation is not for you, you might find it more appealing to walk through a simple metal analysis.
We implemented the meta analysis methodology in an microsoft excel addin which is freely available and incorporates more meta analysis models including the iterative maximum likelihood and profile likelihood than are usually available, while paying particular attention to the userfriendliness of the package. Free downloads comprehensive metaanalysis software. Gwa metaanalysis metal practical in this practical we will run a. Metal analysis is important for environmental protection and public health. May, 2016 the most reliable source of evidence based medicine. This archive includes a small example of how metal can be used to meta analyze study results. Metaanalysis software forest plot radial plot ncss. Metal provides a rich scripting interface and implements efficient memory management to allow analyses of very large data sets and to support a variety of input file formats. Metal provides a rich scripting interface and implements efficient memory management to allow analyses of very large data sets and to support a. The chromosome and position fields are propagated to the metaanalysis result file useful when generating manhattan or locuszoom plots. Metaanalysis is a research process used to systematically synthesise or merge the findings of single, independent studies, using statistical methods to calculate an overall or absolute effect.
Toxic metals in drinking water is strictly regulated. The example is drawn from a recent study of the genetics of glucose levels chen et al, journal of clinical investigation, 2008. Which is the best tool for metaanalysis of gwas data. Ncss includes tools for performing meta analysis of means, proportions, correlated proportions, and hazard ratios. If you use metal please fill out a copy of the registration form or email goncalo abecasis. Meta analysis is a statistical technique for combining the findings from independent studies. In implementing our software for metaanalysis, a primary. Meta analysis of trials provides a precise estimate of. While the worked example is the analysis of a correlational dataset, the general metaanalytic process described in this paper is applicable for all types of effect sizes. Metaanalysis in medical research pubmed central pmc. To enable correction for sample overlap in your sample size weighted meta analysis, use. The analysis should include published and unpublished results to avoid publication bias.
The standard approach to trend estimation in meta analysis of exposureresponse relations when only published categoryspecific relative risks and their confidence intervals are available is to fit a weighted linear regression through the origin, in which the dependent variable is the estimated log relative risk, the independent variable is the. The name mix comes from metaanalysis in excel and 2. I am performing a metaanalysis of multiple gwas data and now, after an intensive qc, i have to choose a suitable software for doing it. The meta analysis procedures in ncss are easytouse and validated for accuracy. Other metal analysis needs to be preformed in groundwater, surface water, wastewater, solid waste, soils, and sludge. Fictitious example do individuals who wear sunscreen have fewer cases of melanoma than those who do not wear sunscreen. The metafor package implements various meta analytic models, methods, and techniques that have been described in the literature. The links below demonstrate how the models, methods, and techniques described in the respective articleschapters can be applied via the metafor package. The classical meta analysis compares two treatments while network meta analysis or multiple treatment metaanalysis can provide estimates of treatment efficacy of multiple treatment regimens, even when direct comparisons are unavailable by indirect comparisons 60. Metal provides a computationally efficient tool for meta analysis of genomewide association scans, which is a commonly used approach for improving power complex traits gene mapping studies.
77 1381 190 1001 1001 1117 553 296 687 1058 90 297 1278 399 1311 1536 650 1216 832 745 473 193 1247 21 1019 1360 309 1406 137 634 1322 1443 147 1221 279 615 710