time series and principal components

Posted by Art Kendall on Dec 27, 2021; 3:38pm
URL: http://spssx-discussion.165.s1.nabble.com/time-series-and-principal-components-tp5740917.html

I am reviewing a journal submission that has some elements that are outside my expertise.  The goal of my post are
(1)to be able to suggest to the author from an some ways to relate the approach to an audience that includes social/behavioral scientists and policy makers from different language backgrounds.
(2)suggest to the editor what to look for in reviewers of the econometric aspects,

I have much experience with principal components and principal factors where the "repeated" variables are items for a summative scales to represent constructs like values, attitudes, abilities, achievement, etc.

I no longer have access to journals etc.  Does anybody have a link to a crosswalk between the vocabulary of time series and the vocabulary of factor analysis in the social behavioral (SB) sciences?

How does TS deal with having more variables (repeats) than cases? In SB there is a rule of thumb that fewer than 10 times as many cases as variables is highly questionable.
How does TS deal with accounting for total variance vs common variance?
How does TS deal with corrected item-total correlation, the correlation of each item with the sum of the other correlations?

In social/behavioral sciences one does not include items and their total/mean in the same "factor analysis", what would make it sensible to have 3 variables that are counts plus the total of the three in a PCA?