[R-meta] Subgroup analyses

[David Cicchetti]

Dear list members,

I am trying to run subgroup analyses in my meta analysis. I have the  
issue that I do not know whether I should include an intercept or not,  
meaning whether I should do mods = ~ Coil.Type (with intercept) or  
mods = ~ Coil.Type - 1 (without intercept).

 From what I know so far we can leave out the intercept if for x = 0  
-> y = 0. Unfortunately I don't think that logic applies here. My  
variables (as for example Coil Type) do not have a 'zero' condition,  
it compares for example Coil A with Coil B.
If I want to write down the values as a table, I cannot do that well  
when including the intercept because then the estimate, standard error  
and CI are from the difference to the intercept and not from the level  
itself.

Since the Moderator tests become more easily significant when  
excluding the intercept, I was hesitant to do so. Therefore I would be  
thankful if anyone could clear me up on when/if I am allowed to get  
rid of the Intercept in my case.

Thanks in advance.

Best,
David