<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=utf-8" http-equiv=Content-Type>
<STYLE>
BLOCKQUOTE {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; MARGIN-LEFT: 2em
}
OL {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
UL {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
P {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
DIV.FoxDiv20130516122249577824 {
LINE-HEIGHT: 1.5; MARGIN: 10px; FONT-FAMILY: Calibri; COLOR: #000080; FONT-SIZE: 10.5pt
}
DIV.FoxDiv20130517101334286385 {
LINE-HEIGHT: 1.5; MARGIN: 10px; FONT-FAMILY: Calibri; COLOR: #000080; FONT-SIZE: 10.5pt
}
BODY {
LINE-HEIGHT: 1.5; FONT-FAMILY: Calibri; COLOR: #000080; FONT-SIZE: 10.5pt
}
</STYLE>
<META name=GENERATOR content="MSHTML 9.00.8112.16483">
<STYLE>BLOCKQUOTE {
MARGIN-TOP: 0px
}
OL {
MARGIN-TOP: 0px
}
UL {
MARGIN-TOP: 0px
}
</STYLE>
<STYLE>BLOCKQUOTE {
MARGIN-TOP: 0px
}
OL {
MARGIN-TOP: 0px
}
UL {
MARGIN-TOP: 0px
}
</STYLE>
</HEAD>
<BODY style="MARGIN: 10px">
<DIV> Hello.</DIV>
<DIV>
<DIV class=FoxDiv20130517101334286385>
<DIV>
<DIV class=FoxDiv20130516122249577824>
<DIV>I am trying to perform meta-analysis on some before-after studies. These
studies are designed to clarify if there is any
significant metabolic change before and after an intervention. There
is only one group in these studies, i.e., no control group. I followed the
e-mail communication of R-help (<SPAN
style="FONT-STYLE: italic">https://stat.ethz.ch/pipermail/r-help/2012-April/308946.html
</SPAN>) and the Metafor Manual (version 1.8-0, released 2013-04-11, relevant
contents can be found on pages of 59-61 under
'Outcome Measures for Individual Groups '). I made a trial
analysis and attached the output here, I wonder if anyone can look through it
and give me some comments. </DIV>
<DIV> </DIV>
<DIV>I have three questions about the analysis:</DIV>
<DIV> </DIV>
<DIV>1) Most studies reported the before-and-after raw change as
Mean+/-SD, but few of them have reported the values of
before-intervention (mean_r and sd_r) and the values of after-intervention
(mean_s and sd_s), and none of them reported the r value (correlation for the
before- and after- intervention measurements). Based on the guideline
of the Metafor manual, I set the raw mean change as m1i (i.e., raw mean
change=mean_s=m1i), and set the standard deviation of raw change as sd1i (i.e.,
the standard deviation of raw change =sd_s=sd1i), and set all other arguments
including m2i, sd2i, ri as 0, and then calculated the standardized mean
change using change score (SMCC). I am not sure if all these settings are
correct.</DIV>
<DIV> </DIV>
<DIV>2) A few studies have specified individual values of m1i, m2i,
sd1i, sd2i , but did not report the change score or its sd. So can I set r=0 and
use these values to calculate SMCC? Since SMCC is not calculated in the
same way like 1), will this be a problem?</DIV>
<DIV> </DIV>
<DIV>3) some studies reported the percentage mean changes instead of raw mean
change (percentage change=(value of after-intervention - value of before
intervention) / value of before intervention), I think it may not be the right
way to simply substitute the raw mean change with the percentage mean
changes. Is there any method to deal with this problem?</DIV>
<DIV> </DIV>
<DIV>Any comments are welcome.</DIV>
<DIV> </DIV>
<DIV>With best regards.</DIV>
<DIV> </DIV>
<DIV>
<HR style="WIDTH: 210px; HEIGHT: 1px" align=left color=#b5c4df SIZE=1>
</DIV>
<DIV><SPAN>Qiang Yue</SPAN></DIV>
<DIV> </DIV></DIV></DIV></DIV></DIV></BODY></HTML>