[R-meta] rma.mv-When a higher level can't be modeled because of one row

[Viechtbauer, Wolfgang (SP)]

On further though, I would then just ignore 'measure' altogether. Definitely do not use it at the top of a random effects hierarchy as that would induce possible dependence for all 499 rows falling under measure = 1 based on a very poor variance estimate.

Best,
Wolfgang

>-----Original Message-----
>From: Farzad Keyhan [mailto:f.keyhaniha using gmail.com]
>Sent: Monday, 08 November, 2021 17:13
>To: Viechtbauer, Wolfgang (SP)
>Cc: R meta
>Subject: Re: rma.mv-When a higher level can't be modeled because of one row
>
>The actual data has 500 rows. That is just the structure of the data
>that I showed. That is why I want to make sure if it is reasonable to
>ignore 499 rows that agree with "measure/study" and just base my
>random effect specification on one row that suggests "study/measure".
>
>In other words, I want to make sure my random-effects seem a bit more
>in line with the generality of my data rather than an exception that
>has occurred in just one row.
>
>Is there a consequence if I switch from "measure/study" to
>"study/measure" given this situation?
>
>On Mon, Nov 8, 2021 at 10:00 AM Viechtbauer, Wolfgang (SP)
><wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
>>
>> Like I said before, if this is really all the data, then I wouldn't do any of
>that, because this will be a way too complex model for so little data.
>>
>> >-----Original Message-----
>> >From: Farzad Keyhan [mailto:f.keyhaniha using gmail.com]
>> >Sent: Monday, 08 November, 2021 16:51
>> >To: Viechtbauer, Wolfgang (SP)
>> >Cc: R meta
>> >Subject: Re: rma.mv-When a higher level can't be modeled because of one row
>> >
>> >Sure, so, I shouldn't worry that all rows but one suggest
>> >"measure/study" and only because of that one exceptional row, do: "~ 1
>> >| study/measure/outcome" or "~ 1 | study/outcome/measure"?
>> >
>> >Fred
>> >
>> >On Mon, Nov 8, 2021 at 9:39 AM Viechtbauer, Wolfgang (SP)
>> ><wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
>> >>
>> >> No, I meant using "~ 1 | study/measure/outcome" or "~ 1 |
>> >study/outcome/measure".
>> >>
>> >> Best,
>> >> Wolfgang
>> >>
>> >> >-----Original Message-----
>> >> >From: Farzad Keyhan [mailto:f.keyhaniha using gmail.com]
>> >> >Sent: Monday, 08 November, 2021 16:22
>> >> >To: Viechtbauer, Wolfgang (SP)
>> >> >Cc: R meta
>> >> >Subject: Re: rma.mv-When a higher level can't be modeled because of one row
>> >> >
>> >> >Thanks Wolfgang.
>> >> >
>> >> >Yes, this is just the data structure. Focusing on the "making
>> >> >[measure] nested within study" part of your suggestion, you mean in
>> >> >row # 3, I recode the "measure" value of 1 to 2, or even delete row #
>> >> >3 altogether, or "~1 | measure/study/outcome" by default will take
>> >> >care of making "measure" nested in study?
>> >> >
>> >> >Thank you,
>> >> >Fred
>> >> >
>> >> >On Mon, Nov 8, 2021 at 4:13 AM Viechtbauer, Wolfgang (SP)
>> >> ><wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
>> >> >>
>> >> >> Dear Fred,
>> >> >>
>> >> >> I would consider using measure as a fixed effect or making it nested
>within
>> >> >study (or within outcome). But none of this might really be appropriate for
>a
>> >> >dataset this small (but I assume this was just constructed for illustrating
>> >your
>> >> >question).
>> >> >>
>> >> >> Best,
>> >> >> Wolfgang
>> >> >>
>> >> >> >-----Original Message-----
>> >> >> >From: Farzad Keyhan [mailto:f.keyhaniha using gmail.com]
>> >> >> >Sent: Friday, 05 November, 2021 2:59
>> >> >> >To: R meta
>> >> >> >Cc: Viechtbauer, Wolfgang (SP)
>> >> >> >Subject: Re: rma.mv-When a higher level can't be modeled because of one
>row
>> >> >> >
>> >> >> >For clarity, by a solution, I mean how can I account for the
>> >> >> >heterogeneity in true effects attributable to "measure", while
>> >> >> >"measure" is neither a perfect candidate for being the nestor of
>> >> >> >study:
>> >> >> >
>> >> >> >random = ~1 | measure/study/outcome
>> >> >> >
>> >> >> >nor a perfect candidate for being crossed with study:
>> >> >> >
>> >> >> >random = list(~1 | study/outcome, ~1|measure)
>> >> >> >
>> >> >> >Thank you,
>> >> >> >Fred
>> >> >> >
>> >> >> >On Thu, Nov 4, 2021 at 2:26 PM Farzad Keyhan <f.keyhaniha using gmail.com>
>wrote:
>> >> >> >>
>> >> >> >> Dear Experts,
>> >> >> >>
>> >> >> >> In my toy data below, if in row # 3, "measure" was 2 (instead of 1),
>> >> >> >> then, I could take "measure" as a level higher than study:
>> >> >> >>
>> >> >> >> random = ~1 | measure/study/outcome
>> >> >> >>
>> >> >> >> But right now, because in study 2 (rows # 3 and 4) "measure" can vary,
>> >> >> >> "measure" can't be considered a level higher than study.
>> >> >> >>
>> >> >> >> On the other hand, because "measure" varies only in one study, I can't
>> >> >> >> take "measure" as a crossed random-effect either.
>> >> >> >>
>> >> >> >> I was wondering what solutions the expert list members might have for
>> >> >> >> this situation?
>> >> >> >>
>> >> >> >> Thanks,
>> >> >> >> Fred
>> >> >> >>
>> >> >> >>    measure       row   study   outcome
>> >> >> >>    1             1     1       1
>> >> >> >>    1             2     1       2
>> >> >> >> #  1             3     2       1 <--- measure on this row
>> >> >> >>    2             4     2       1
>> >> >> >>    1             5     3       1
>> >> >> >>    1             6     3       2