Description Usage Arguments Value Author(s) References Examples

Compute variance-covariance matrix for multivariate meta-analysis when effect size is mean difference.

1 | ```
md.vcov(r,nt,nc,n_rt=0,n_rc=0,sdt,sdc)
``` |

`r ` |
A list of correlation coefficient matrices of the outcomes from the studies. r[[k]][i,j] is the correlation coefficient between outcome i and outcome j from study k. |

`nt ` |
A matrix with sample sizes in the treatment group reporting each of the outcome. nt[i,j] is the sample size from study i reporting the outcome j. |

`nc ` |
Defined in a similar way as nt for control group. |

`n_rt ` |
A list of matrices storing sample sizes in the treatment group reporting pairwised outcomes in the off diagonal elements. n_rt[[k]][i,j] is the sample size reporting both outcome i and outcome j from study k. Diagonal elements of these matrices are not used. The default value is zero, which means the smaller sample size reporting the corresponding two outcomes: i.e. n_rt[[k]][i,j]=min(nt[k,i],nt[k,j]). |

`n_rc ` |
Defined in a similar way as n_rt for control group. |

`sdt ` |
Sample standard deviation from each of the outcome. sdt[i,j] is the sample standard deviation from study i for outcome j. |

`sdc ` |
Defined in a similar way as sdt for control group. |

list.md.cov | A list of computed variance-covariance matrices. |

md.cov | A matrix whose rows are computed variance-covariance vectors. |

Min Lu

Ahn, S., Lu, M., Lefevor, G.T., Fedewa, A. & Celimli, S. (2016). Application of meta-analysis in sport and exercise science. In N. Ntoumanis, & N. Myers (Eds.), *An Introduction to Intermediate and Advanced Statistical Analyses for Sport and Exercise Scientists* (pp.233-253). Hoboken, NJ: John Wiley and Sons, Ltd.

Wei, Y., & Higgins, J. (2013). Estimating within study covariances in multivariate meta-analysis with multiple outcomes. *Statistics in Medicine, 32*(7), 119-1205.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | ```
######################################################
# Example: Geeganage2010 data
# Preparing covariances for multivariate meta-analysis
######################################################
## set the correlation coefficients list r
r12=0.71
r.Gee=lapply(1:nrow(Geeganage2010),function(i){matrix(c(1,r12,r12,1),2,2)})
computvocv<-md.vcov(nt=subset(Geeganage2010, select=c(nt_SBP,nt_DBP)),
nc=subset(Geeganage2010, select=c(nc_SBP,nc_DBP)),
sdt=subset(Geeganage2010, select=c(sdt_SBP,sdt_DBP)),
sdc=subset(Geeganage2010, select=c(sdc_SBP,sdc_DBP)),
r=r.Gee)
# name variance-covariance matrix as covars
covars = computvocv$md.cov
#####################################################
# Running random-effects model using package "mvmeta"
#####################################################
#library(mvmeta)
#mvmeta_RE = summary(mvmeta(cbind(MD_SBP,MD_DBP),S=covars,
# data=subset(Geeganage2010,select=c(MD_SBP,MD_DBP)),
# method="reml"))
#mvmeta_RE
``` |

```
Loading required package: corpcor
```

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