[R] Meta-analysis with zero values for mean and sd. Continuous data.

[Uwe Ligges]

On 09.07.2011 13:14, aletheia wrote:
> Hi!
> I want to do a meta-analysis with count data for treatement/control cases.
> Mi problem is that I need to use zero values (an informative value) for the
> mean and standard deviation for one of the treatement, but R has a problem:
> "Studies with zero values for sd.e or sd.c get no weight in meta-analysis".
> I can agroup the case by Family (byvar=Family).

I wonder how you can have a standard deviation of 0 in one or more 
studies. This cannot be true and is what you have to check.

Best,
Uwe Ligges



> ¿anybody help me? Thanks!
>
>
>> datos<-read.table(file="datos_totales.csv",head=TRUE,sep=",",dec=",")
>> datos[10:20,]
>              Study ControlN ControlMean ControlSD TreatedN TreatedMean
> TreatedSD       Family
> 10 Ali.Gmb.S1.Inv        3    893.3333 180.36999        3  1213.33333
> 410.52812 Capitellidae
> 11 Ali.Gmb.S2.Inv        3    640.0000 348.71192        3   666.66667
> 220.30282 Capitellidae
> 12 Ali.Gmb.S3.Inv        3    426.6667 184.75209        3   920.00000
> 628.64935 Capitellidae
> 13 Ali.Cul.S1.Ver        3    213.3333 115.47005        3     0.00000
> 0.00000 Cirratulidae
> 14 Ali.Cul.S2.Ver        3    160.0000 144.22205        3    40.00000
> 40.00000 Cirratulidae
> 15 Ali.Cul.S3.Ver        3    293.3333 234.37861        3    26.66667
> 46.18802 Cirratulidae
> 16 Ali.Cul.S1.Inv        3    653.3333 532.66625        3    13.33333
> 23.09401 Cirratulidae
> 17 Ali.Cul.S2.Inv        3    706.6667 335.45988        3    26.66667
> 23.09401 Cirratulidae
> 18 Ali.Cul.S3.Inv        3    666.6667 674.48746        3    80.00000
> 80.00000 Cirratulidae
> 19 Ali.Gmb.S1.Ver        3    280.0000  69.28203        3     0.00000
> 0.00000 Cirratulidae
> 20 Ali.Gmb.S2.Ver        3    226.6667 220.30282        3     0.00000
> 0.00000 Cirratulidae
>
>>   library(meta)
>
>>
>> metaanalisis2<-metacont(TreatedN,TreatedMean,TreatedSD,ControlN,ControlMean,ControlSD,data=datos,byvar=Family,label.c="Control",print.byvar=FALSE,label.e="Treatment",studlab=Study)
> *Mensajes de aviso perdidos
> In metacont(TreatedN, TreatedMean, TreatedSD, ControlN, ControlMean,  :
>    Studies with zero values for sd.e or sd.c get no weight in meta-analysis*
>
> --
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>
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