Dear Thiago, dear Michael,
I read this thread and I still am not clear about the nature of the data. Are these really compositional data, or simple proportions? The difference is:
Compositional data are characterized by lacking a denominator (no "n", no sample size). For each study, you have only percentages that add to 100%. Such data occur in microbioma research (percentages of species in the microbioma).
By contrast, proportions are given as r (number of events) and n (sample size, i.e., number of persons/patients/trials/whatever), or as percentages and n.
If you have proportions, you may use metaprop. If you have compositional data, as Michael supposed, you cannot.
Best,
Gerta
Am 08.03.2022 um 12:34 schrieb Thiago Roza:
Dear Michael,
Thank you for your reply!
Do you think it would be possible to generate pooled proportions for
at least the most commonly reported suicide method in this case? (I
would organize my dataset in the following format: "suicide by
hanging" vs "other method of suicide", only two categories).
Thank you,
Thiago
Em seg., 7 de mar. de 2022 ?s 13:40, Michael Dewey
<lists at dewey.myzen.co.uk> escreveu:
Dear Thiago
What you have is compositional data which might prove a useful search
term. A common way to analyse such data is by taking the ratios of the
components to a reference one and then taking logs. However that is
about the sum total of my knowledge of compositional data analysis and
as far as I know there is no extant R package which deals with it.
Others on the list may have better ideas.
For future reference if you post on CrossValidated it is best to put a
link in each of them so people can check if it has already been answered
in the other place.
Michael
On 06/03/2022 16:36, Thiago Roza wrote:
Dear all,
I am conducting a meta-analysis about characteristics of suicide
deaths in post-mortem studies. My aim is to describe pooled
proportions of key characteristics (biological sex, suicide site,
race, marital status, suicide method, the proportion of substance use
near death, proportion of psychiatric diagnosis prior to death, etc)
across the included studies. Initially, I thought that "metaprop" from
the package "meta" would be enough to pool all these proportions
across included studies. Nevertheless, some of these variables have
more than one category (i.e. suicide method has more than 10
categories: such as hanging, firearm, poisoning, etc), and the pooling
of the proportion of each suicide method separately produces results
which when summed up give more than 100% for the summed proportion of
all suicide methods. Therefore, my first question is: is it possible
to pool all those proportions using "metaprop"? If yes, could anyone
give an example about the coding for the pooling of proportions in the
case of suicide methods? If not, is there any other package that would
allow me to pool the aggregate proportion of suicide methods?
Thank you,
Thiago Roza