[R-meta] Accounting for sources of variation in meta-analysis

[Michael Dewey]

Dear Carla

Can you expand a little on this? At the moment what estimates go into 
your current meta-analysis? Are they some relationship between land use 
and service provision? And do you have a single potential measure of 
biodiversity for each current estimate? If you do then a first step 
might be to use biodiversity as a moderator in a meta-regression.

Michael

On 19/03/2018 03:53, Carla Gomez Creutzberg wrote:
> Dear fellow meta-analysts:
> 
> I hope this message finds you all well.
> 
> I have collected information on the provision of ecosystem services by
> different land uses and have conducted a meta- analysis on this. However, I
> now wish to expand this analysis to a subset of our meta-dataset that,
> besides the effect of different land uses on ecosystem service provision,
> also has data on the biodiversity of each land use. I would like to use
> this to explore if biodiversity accounts for some (or all) of the effect we
> see of land use on ecosystem service provision.
> 
> After reading a bit, I am beginning to think that one of the ways that we
> could probably use to approach this analysis would be a long the lines of
> MASEM (Meta-analytic structural equation modelling) or a structural
> equation modelling -based meta-analysis. I am entirely sure yet which one
> applies best to our case yet but probably its the second one, which seems
> to be not so well documented. In any case, at this stage, both options seem
> a bit intimidating and complex so I was wondering if anybody knew of any
> alternative methods to separate the effect of land use and biodiversity in
> the provision of ecosystem services within our datset? I am not sure if
> taking biodiversity as a moderator would be of any help with this? In our
> dataset, for each study, we have information on 2 or more land uses, and
> for each land use we have an indicator of ecosystem service provision and
> an indicator biodiversity.
> 
> What ultimately interests us is the effect of land use on ecosystem
> services with and without accounting for biodiversity. However, I am
> concerned that to tease this apart we may need to eventually have
> biodiversity as a response to land use and ecosystem services as a response
> to land use as well which could give rise to problems with non-independence
> since we would have 2 effect sizes per study.
> 
> Any insights or suggestions on this are certainly most welcome.
> 
> 
> Thanks for you attention!
> 
> 

-- 
Michael
http://www.dewey.myzen.co.uk/home.html