[R-sig-ME] measuring carry-over effects in mixed models

[Simon Harmel]

Dear Phillip,

Thank you for your response. Could you possibly elaborate on
"Depending on the exact nature of the carryover effect"?

Also, how are the "lead/lag predictors" often created?

My data has the following general structure.

m<-"
   student group  time
         1 C         0
         1 C         1
         1 C         2
         1 C         3
         1 T         0
         1 T         1
         1 T         2
         1 T         3
         2 C         0
         2 C         1
         2 C         2
         2 C         3
         2 T         0
         2 T         1
         2 T         2
         2 T         3"

data <- read.table(text=m,h=T)

Simon


On Tue, Mar 1, 2022 at 11:12 PM Phillip Alday <me using phillipalday.com> wrote:
>
> Depending on the exact nature of the carryover effect, the usual
> suspects would be:
>
> 1. using an autoregressive model of some type
> 2. including lead/lag predictors in your model, e.g.
>         lmer(y ~ time*group*prev_time + [covariates] + (1 | student))
>
> But note that the initial timepoint doesn't have a prev_time and so
> there is a missing value there.
>
> Phillip
>
> On 17/2/22 12:32 pm, Simon Harmel wrote:
> > Hello All,
> >
> > I'm analyzing the data from my longitudinal study whose design can be
> > depicted as (view the following in plain text):
> >
> > O1  X1  O2  X2  O3  X3  O4
> > O1      O2      O3      O4
> >
> > where Xs denote subtitled videos given to the treatment group and Os
> > denote measurement occasions.
> >
> > My current model is:  lmer(y ~ time*group + [covariates] + (1 | student))
> >
> > However, I'm also interested in measuring the "carry-over effects" of
> > watching subtitled videos at each occasion to the subsequent
> > occasions.
> >
> > For instance, I want to know how much watching the subtitled video at
> > the first occasion (O1) impacts the treated students' performance at
> > later occasions (O2 and O3) etc.
> >
> > I wonder if any changes to my model can enable me to measure these
> > carry-over effects or if any other R package may provide such
> > functionality?
> >
> > Many thanks,
> > Simon
> >
> > _______________________________________________
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> >