[R-meta] Distinguishing between the design of longitudinal studies

[Stefanou Revesz]

Hi James,

Thank you very much. I fully understand that the details of how each
design was implemented could lead to the formation of a bunch of
different moderators.

But, we are wondering, *purely by the way the designs are set up*,
what features (e.g., *in terms of threats to internal validity*,
*ranking of design's face quality* etc.) could potentially distinguish
between these three designs?

As I'm writing this response, for example can we perhaps rank these
designs based on how they each lend themselves to say carry-over
effect/practice effect or fatigue? Any other threats to internal
validity or design's face quality that can be coded for?

Thank you,
Stefanou

R o x o o
R o    o o   <-- control group


R o x o x o  o
R o    o    o  o  <-- control group


R o x x x o  o
R o         o  o  <-- control group

On Tue, Aug 31, 2021 at 11:51 AM James Pustejovsky <jepusto using gmail.com> wrote:
>
> Hi Stefanou,
>
> This is certainly an interesting question but I, for one, am at a loss as to what advice to give. What moderators to include in your model depends first and foremost on the research questions that you are investigating through your meta-analysis and, second, on the substantive and design-related features of the included studies. We on the listserv are not in a very good position to offer guidance here, since we don't have the context of or experience in your research area.
>
> All that said, if you have thoughts or ideas for how to proceed with your meta-analysis, you are of course certainly welcome to solicit feedback through the listserv.
>
> Kind Regards,
> James
>
> On Mon, Aug 23, 2021 at 12:57 AM Stefanou Revesz <stefanourevesz using gmail.com> wrote:
>>
>> Dear List Members,
>>
>> We are meta-analyzing a number of longitudinal studies. But our
>> studies have three general research designs (below).
>>
>> We are wondering, other than creating study-level moderators to
>> distinguish between the designs or how many treatments each study uses
>> etc., what *time-level* or *effect-size-level* moderators we should
>> control for in our meta-analysis?
>>
>> First, we have studies that make an observation (o) prior to a
>> treatment (x), and then, make follow-up observation(s):
>>
>> o x o o
>> o    o o   <-- control group
>>
>> Second, we have studies that make an observation (o) prior to a
>> treatment (x), then, make follow-up observation on that treatment, but
>> then again introduce the treatment and make follow-up observation(s):
>>
>> o x o x o  o
>> o    o    o  o  <-- control group
>>
>> Third, we have studies that make an observation (o) prior to
>> successive treatments (x), and then, make follow-up observation(s) on
>> those treatments:
>>
>> o x x x o  o
>> o         o  o  <-- control group
>>
>> Thank you!
>> Stefanou
>>
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