Re: Temporal stability using multilevel modeling

Posted by Bruce Weaver on
URL: http://spssx-discussion.165.s1.nabble.com/Temporal-stability-using-multilevel-modeling-tp5736274p5736281.html

Perhaps Oliver posted via Nabble without first joining the actual mailing
list?  Oliver, if you have not joined the mailing list, click the "more
options" link at the top of the Nabble archive page.  

Jon, you can see Oliver's original post and the rest of the thread here:

http://spssx-discussion.1045642.n5.nabble.com/Temporal-stability-using-multilevel-modeling-td5736274.html

HTH.


Jon Peck wrote
> I have not seen the original post, but if this question is really about
> stationarity, then the AR coefficients would be very relevant, and there
> are necessary and sufficient conditions for this based on them.
>
> On Sun, Jun 24, 2018 at 8:17 PM Marc O Martel <

> momartel.bwh.harvard@

>> wrote:
>
>> Rich & Andy,
>>
>>
>> Thank you for sharing your thoughts about this. That's very useful.
>>
>>
>> Best,
>>
>> MO.
>>
>> ------------------------------
>> *From:* Rich Ulrich &lt;

> rich-ulrich@

> &gt;
>> *Sent:* Saturday, June 23, 2018 8:12 PM
>> *To:*

> SPSSX-L@.UGA

> ; Oliver
>> *Subject:* Re: Temporal stability using multilevel modeling
>>
>>
>> Like Andy, I'm not speaking to the SPSS questions, either, and I think
>>
>> AR1 won't be useful. Here are other reasons.  Dichotomous measures
>>
>> need more cases to match the power achieved by continuous measures.
>>
>>
>> Six points is an awfully small time series for continuous data for using
>> "time
>>
>> series methods", I think.  No doubt there are exceptions. You do have 100
>>
>> parallel series ... which isn't the standard TS problem. My practical
>> experience
>>
>> with Time series is zero, but, unfortunately for your prospect of getting
>> a better
>>
>> answer here, we've dealt with very few TS problems, and I suspect that we
>>
>> have no experts here of that specialty.
>>
>> The stock markets call their instability "lability" and they measure it
>> from the
>>
>> standard deviation or variance of stock prices. Variance of a dichotomy
>> is
>> computed
>>
>> from its mean (i.e., proportion), so I suggest that you get a transparent
>> and obvious
>>
>> measure of stability/volatility by counting and reporting the number of
>> changes
>>
>> observed for each ID.   (By the way, if most of your scores for a subject
>> are identical,
>>
>> at zero or 1, you have a different problem of lack-of-usable-variance for
>> analysis.)
>>
>>
>> --
>>
>> Rich Ulrich
>> ------------------------------
>> *From:* SPSSX(r) Discussion &lt;

> SPSSX-L@.UGA

> &gt; on behalf of
>> Oliver &lt;

> momartel.bwh.harvard@

> &gt;
>> *Sent:* Saturday, June 23, 2018 9:22:42 AM
>> *To:*

> SPSSX-L@.UGA

>> *Subject:* Temporal stability using multilevel modeling
>>
>> Hi everyone,
>>
>> I'm interested in examining the temporal stability of a behavior that was
>> measured at 6 different time points (i.e., once a month for 6 consecutive
>> months). My sample includes 100 patients, and most of them have data on
>> the
>> 6 time points.  I have three questions:
>>
>> 1) For the whole sample, would it be possible to use AR1 as a measure of
>> temporal stability of the behavior ? Given that AR1 has often been
>> described
>> as a measure of "temporal dependency", this seems to make sense. It is
>> important to note, however, that there are minor between-person
>> variations
>> in time intervals in-between each of the assessment time points, which is
>> typical in clinical research. Perhaps AR1 requires a pure "time-series"
>> design with equally spaced intervals in between assessments ?
>>
>> 2) My behavior of interest is a binary variable (i.e., presence/absence).
>> I
>> tried to get the AR1 using the GLMM procedure in SPSS, and the AR1 is not
>> generated. Is it possible to get AR1 with a binary outcome ? If so, is
>> there
>> any syntax specification needed ? If not, is there an alternative to AR1
>> with a binary outcome ?
>>
>> 3) The second goal of my study is to examine the within-person (i.e.,
>> Level
>> 1) predictors of behavior stability. Therefore, I was wondering whether
>> it
>> would be possible to derive a within-person indicator (e.g., AR1) of
>> behavior stability ? If so, I could use this indicator as an outcome
>> measure, which could then be predicted by other within-person (i.e.,
>> Level
>> 1) variables.
>>
>> Thanks in advance to all of you for your help.
>> Oliver
>>
>>
>>
>> --
>> Sent from: http://spssx-discussion.1045642.n5.nabble.com/
>> SPSSX Discussion | Mailing List Archive
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>
> --
> Jon K Peck

> jkpeck@

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-----
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