[R] questions about meta-analysis

[Michael Dewey]

At 06:02 27/06/2009, sdzhangping wrote:
>Dear R users:
>
>In the example of meta-analysis (cochrane, package rmeta), I can not 
>found the p-value of Test for overall effect, and some other indices 
>(Z, I, weight and et al).  How can I get the these indices listed?
> > library(rmeta)
> > data(cochrane)
> > cochrane
>           name ev.trt n.trt ev.ctrl n.ctrl
>1     Auckland     36   532      60    538
>2        Block      1    69       5     61
>3        Doran      4    81      11     63
>4        Gamsu     14   131      20    137
>5     Morrison      3    67       7     59
>6 Papageorgiou      1    71       7     75
>7      Tauesch      8    56      10     71
> > a=meta.MH(n.trt,n.ctrl,ev.trt,ev.ctrl,names=name,data=cochrane)

If at this point you do str(a) you will find what a contains which 
may or may not help you answer your question.
Similarly str(summary(a)) may also be revealing.

Of course R lets you do anything you want but if the author did not 
print out a test and a p-value you might like to ask yourself whether 
that  suggests anything (as someone has already pointed out in another reply).

> > summary(a)
>Fixed effects ( Mantel-Haenszel ) meta-analysis
>Call: meta.MH(ntrt = n.trt, nctrl = n.ctrl, ptrt = ev.trt, pctrl = ev.ctrl,
>     names = name, data = cochrane)
>------------------------------------
>                OR (lower  95% upper)
>Auckland     0.58    0.38       0.89
>Block        0.16    0.02       1.45
>Doran        0.25    0.07       0.81
>Gamsu        0.70    0.34       1.45
>Morrison     0.35    0.09       1.41
>Papageorgiou 0.14    0.02       1.16
>Tauesch      1.02    0.37       2.77
>------------------------------------
>Mantel-Haenszel OR =0.53 95% CI ( 0.39,0.73 ) (where is Z and p-value ?)
>Test for heterogeneity: X^2( 6 ) = 6.9 ( p-value 0.3303 )
>
>
>
>Thanks
>Yours Ping Zhang
>
>
>         [[alternative HTML version deleted]]

Michael Dewey
http://www.aghmed.fsnet.co.uk