Thank you, Bert. That's perfect! I will do. On 31 May 2016 21:43, "Bert Gunter" <bgunter.4...@gmail.com> wrote:
> Briefly, as this is off-topic, and inline: > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Tue, May 31, 2016 at 11:32 AM, Dan Kolubinski <kolub...@lsbu.ac.uk> > wrote: > > That makes perfect sense. Thank you, Michael. I take your point about > not > > chasing the data and definitely see the risks involved in doing so. Our > > hypothesis was that the first, second and fourth variables would be > > significant, but the third one (intervention) would not be. > > That is **not** a legitimate scientific hypothesis. Post to a > statistical list like stats.stackexchange.com to learn why not. > > Cheers, > Bert > > > > I will > > double-check the dataset to make sure that there are not any errors and > > will report the results as we see them. I much appreciate you taking the > > time! > > > > Best wishes, > > Dan > > > > On Tue, May 31, 2016 at 12:02 PM, Michael Dewey <li...@dewey.myzen.co.uk > > > > wrote: > > > >> In-line > >> > >> On 30/05/2016 19:27, Dan Kolubinski wrote: > >> > >>> I am completing a meta-analysis on the effect of CBT on low self-esteem > >>> and > >>> I could use some help regarding the regression feature in metafor. > Based > >>> on the studies that I am using for the analysis, I identified 4 > potential > >>> moderators that I want to explore: > >>> - Some of the studies that I am using used RCTs to compare an > intervention > >>> with a waitlist and others used the pre-score as the control in a > >>> single-group design. > >>> - Some of the groups took place in one day and others took several > weeks. > >>> - There are three discernible interventions being represented > >>> - The initial level of self-esteem varies > >>> > >>> Based on the above, I used this command to conduct a meta-analysis > using > >>> standarized mean differences: > >>> > >>> > >>> > >>> MetaMod<-rma(m1i=m1, m2i=m2, sd1i=sd1, sd2i=sd2, n1i=n1, n2i=n2, > >>> mods=cbind(dur, rct, int, level),measure = "SMD") > >>> > >>> > >> You could also say mods = ~ dur + rct + int + level > >> > >> > >>> > >>> Would this be the best command to use for what I described? Also, what > >>> could I add to the command so that the forest plot shows a sub-group > >>> analysis using the 'dur' variable as a between-groups distinction? > >>> > >>> > >> You have to adjust the forest plot by hand and then use add.polygon to > >> add the summaries for each level of dur. > >> > >> > >>> Also, with respect to the moderators, this is what was delivered: > >>> > >>> > >>> > >>> Test of Moderators (coefficient(s) 2,3,4,5): > >>> QM(df = 4) = 8.7815, p-val = 0.0668 > >>> > >>> Model Results: > >>> > >>> estimate se zval pval ci.lb ci.ub > >>> intrcpt 0.7005 0.6251 1.1207 0.2624 -0.5246 1.9256 > >>> dur 0.5364 0.2411 2.2249 0.0261 0.0639 1.0090 * > >>> rct -0.3714 0.1951 -1.9035 0.0570 -0.7537 0.0110 . > >>> int 0.0730 0.1102 0.6628 0.5075 -0.1430 0.2890 > >>> level -0.2819 0.2139 -1.3180 0.1875 -0.7010 0.1373 > >>> > >>> --- > >>> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 > >>> > >>> > >>> > >> So the totality of moderators did not reach an arbitrary level of > >> significance. > >> > >> > >>> From this, can I interpret that the variable 'dur' (duration of > >>>> > >>> intervention) has a significant effect and the variable 'rct' (whether > a > >>> study was an RCT or used pre-post scores) was just shy of being > >>> statistically significant? I mainly ask, because the QM-score has a > >>> p-value of 0.0668, which I thought would mean that none of the > moderators > >>> would be significant. Would I be better off just listing one or two > >>> moderators instead of four? > >>> > >>> > >> At the moment you get an overall test of the moderators which you had a > >> scientific reason for using. If you start selecting based on the data > >> you run the risk of ending up with confidence intervals and significance > >> levels which do not have the meaning they are supposed to have. > >> > >> > >> Much appreciated, > >>> Dan > >>> > >>> [[alternative HTML version deleted]] > >>> > >>> ______________________________________________ > >>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >>> https://stat.ethz.ch/mailman/listinfo/r-help > >>> PLEASE do read the posting guide > >>> http://www.R-project.org/posting-guide.html > >>> and provide commented, minimal, self-contained, reproducible code. > >>> > >>> > >> -- > >> Michael > >> http://www.dewey.myzen.co.uk/home.html > >> > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > Copyright in this email and in any attachments belongs to London South > Bank University. 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