Features in Detail

MIX 2.0 Lite and Pro

General features of MIX 2.0 Lite

MIX 2.0 Lite is free software for use with Excel 2007 or later. It is meant for those wanting to learn or teach about meta-analysis. This is a fully functional version, except users cannot create or load custom datasets. MIX 2.0 Lite contains 20+ of the data sets used in the most authoritative books on meta-analysis and is ideal for use in educational environments. There is only one license for MIX 2.0 Lite and this is a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License. This means the software is FREE to use and distribute as long as it is not for commercial purposes, the software is not altered, and the software is attributed to the original author.

General features of MIX 2.0 Pro

MIX 2.0 Pro is the full version of the MIX 2.0 software and contains all features of the Lite version (also the built-in data sets), but users can also create and amend their own data sets. In addition, it has a data conversion tool, which can be used to get data from different studies into a compatible format. Like MIX 2.0 Lite, it is compatible with Excel 2007 or later. There are a number of different licenses for MIX 2.0 Pro, including academic and student licenses, and they are priced differently.

Features overview

The basic numerical and graphical meta-analysis features of MIX 2.0 Lite and Pro are identical. The available feature set is very comprehensive and conveniently categorized in exploration, synthesis, and evaluation procedures.

Load built-in datasets (Lite & Pro)

MIX Lite and Pro both contain a large number (currently 20+) built-in data sets. The data sets are from authoritative books on meta-analysis and MIX can therefore be used to reproduce and expand on the analyses and examples presented in the following books:

Create custom datasets (Pro)

MIX 2.0 Pro contains a datawizard that provides a number of options to create custom datasets. The datasets can be of three types:

  • dichotomous outcome data (events and non-events)
  • continuous outcome data (means, standard deviations and group sizes)
  • generic data (study estimate with standard error)

The data can be entered in a dataset template, either manually or via copy-paste procedures or they can be imported in spreadsheet format. In the latter case, MIX 2.0 Pro will create the dataset after the user has identified the rows that contains the data.

Convert effect sizes (Pro)

The data conversion utility in the Data Wizard in MIX 2.0 Pro enables users to convert data types and variability measures for use in MIX 2.0 Pro. If a study provides only a correlation coefficient and a sample size, the data can currently not be entered directly in MIX 2.0. However, the converter can calculate Fisher’s Z and its standard error and make the data compatible with the MIX data entry options. A similar thing can be done for non-comparative rates and sample sizes (proportions), which can be converted with a Freeman-Tukey double arcsine transformation. The converter can also be useful if a study only provides an estimate with a confidence interval, but you really want the estimate and its standard error. The convertor can use data of a single study at a time or apply the conversion to a number of studies at once.

Advanced formatting (Lite & Pro)

As of version 2.015, MIX 2.0 Pro has a convenient feature that allows you to pick preset color schemes. Once a color scheme is set, all new output, plots and tables, will be formatted accordingly. Application of the settings is completely automated. You can even create your own color scheme and save it for later.

You can also customize all plots, either via the regular Excel interface or via some customized dialogs in MIX 2.0. For example, Excel itself has advanced interfaces to format axes and data points, but it does not have the capability to customize labeling of data points. The MIX 2.0 labeler does that for you and allows you to show a custom identifier for one or more data points (e.g. author, publication year, a covariate, or an analysis result).

Publication-quality graphs (Lite & Pro)

MIX 2.0 has the largest arsenal of graphs of all meta-analysis software. The available graphical options are not only very comprehensive, the graphs can also be customized easily via the right-click dialog boxes of Excel 2007. Alternatively, the graphs can be exported to PowerPoint 2007 and, with the vector-based graph items ungrouped, the graph can be adjusted in any way imaginable. The vector-based graphs from MIX result in high-quality imagines no matter how large they are made (the vector-based properties prevent pixelation) and are therefore ideal to create publication-quality graphs. Most journals accept such PowerPoint vector-based image files directly, but they are also easily imported and adjusted in graphical software such as Adobe Photoshop, Adobe Illustrator, or free alternatives such as Gimp and Paint.NET.

Meta-analytical exploration (Lite & Pro)

Numerical output

  • Data set overview
  • Data set summary (studies, N, event scarcity, etc)
  • Heterogeneity statistics (Q with P, I^2 with CI, tau^2 with CI)

Graphical output

  • Simple forest plot
  • Histogram
  • Normal-quantile plot
  • Galbraith plot
  • L’Abbe plot
  • Heterogeneity funnel plot
  • Baujat plot

Meta-analytical synthesis (Lite & Pro)

Numerical output

  • Synthesis details (comparative or control group only, shows study weights and uncertainty statistics)
  • Fixed and random effects models (inverse variance, Mantel-Haenszel, Peto, DerSimonian-Laird one-step, DerSimonian-Laird two-step, Paule-Mandel)
  • Choice of comparative measures for binary outcome data (odds ratio (OR), risk ratio (RR), risk difference (RD)
  • Choice of comparative measures for continuous outcome data (mean difference (MD), Hedges’ G (HG), Cohen’s D (CD)
  • Generic data entry measures (any measure with its standard error, with back transformation of log, logit, arcsine, and Fisher’s z values)
  • Choice of confidence intervals for synthesis results (Z-distribution or T-distribution)
  • Continuity corrections for non-event groups (custom constant value, arm-dependent values)
  • Cumulative synthesis
  • Bayesian posterior calculation

Graphical output

  • Synthesis forest plot (with or without annotation columns)
  • Cumulative forest plot (adding up all studies consecutively)
  • Bayesian triplot m(with prior, likelihood, and posterior)

Meta-analytical evaluation (Lite & Pro)

Numerical output

  • Exclusion sensitivity assessments (single stud exclusion impact)
  • Dissemination selectivity statistics
    • Rank correlation tests (Begg & Mazumdar)
      Regression tests (Egger, Peters, Harbord)
  • Dissemination bias analysis (trim and fill analysis, regression methods are reprogrammed)
  • Subgroup analysis (automatic subgroups based on indicator (categorical) variables
    • Subgroup synthesis table
    • Subgroup forest plot (with or without annotation columns)
  • Subgroup comparison (statistical comparison of subgroup results)

Graphical output

  • Exclusion sensitivity plot
  • Weighting sensitivity plot
  • Selectivity funnel plot
  • Selectivity regression plot
  • Trim and fill plot

Meta-regression and modifier analysis (Lite & Pro)

The meta-regression features are a recent addition and are added step by step. Initially we kept this out of this software, because we felt that serious meta-regression should be done with general statistical software that has more flexibility in terms of tweaking and checking regression methods and results. Due to overwhelming requests for basic meta-regression, we have decided to integrate regression methods into MIX 2.0, as of version 2.015 (end of 2016). We are starting simple, with fixed effect models, and are exploring efficient ways to expand the interface and analysis options.

  • Covariate plot (with weighted regression trend line)
  • Meta-regression table (with corrected standard errors for meta-analysis)