Posted by
paulandpen on
Jan 30, 2007; 12:51am
URL: http://spssx-discussion.165.s1.nabble.com/Help-need-feedback-tp1073543p1073545.html
Hi Debra,
I see there are a few things to considers in this evaluation. A predictor variable by my top of mind definition needs to have a 'causal' influence on a dependent variable. I am not sure how an assessment (without some form of intervention) can be considered a predictor variable (i.e. causes scores on later tests)
Are you actually looking at the 'predictive validity' of the test over time, in other words, will scores found at the first/second point of time actually predict similar scores later on. This is a somewhat different matter for mind, and my first thoughts are test-retest reliability.
Given this is a time-series repeated measures evaluation, you will need to factor in a time-series component to your analysis (that is each person has multiple points of data collected - test scores recorded).
I am thinking as a start that since you have categorical variables, unless I am mistaken, multiple regression is not suitable because the dv is assumed to be continuous in mr, and also that unless you use some specific adjustments to the analysis (time-series regression), results will be distorted because you have repeated measures.
As a start for consideration, I am thinking a repeated measures GLM would be useful (assuming the algorithm is robust enought to handle categorical data). The fixed variable entered into the GLM would be the group exposed to a certain reading assessment at stage 1 or 2, and the time series would be their scores (WITHIN SUBJECT FACTORS) for each of the different test periods. At the very least, this will give you a visual representation via plots of patterns across each time period.
Regards Paul
> Debra Caywood-Rukas <
[hidden email]> wrote:
>
> I am a doctoral student trying to pull together my diss topic and how to
> analyze my data. It's been a few years since my Stats courses and would
> like input.
>
> I my looking to see if 2 different sets of reading assessment (IV's)
> administered in Kindergarten and 1st grade (categorical) are predictive
> of scores received on tests given in 3rd ( categorical) and 4th grade
> (continuous: percentiles, but can convert to categorical), DV's . Can I
> keep continuous or must I convert to categorical?
>
> My data are longitudinal and consists of 153 students who took the 1st
> grade assessments as well as the 3rd and 4th grade tests and a subset of
> that group are 64 students who took the Kindergarten and 1st grade
> assessment as well as the 3rd and 4th grade tests.
>
> I am thinking that I need to analyze the data using Multiple Regression
> multivariate analysis. Including examining if there are any interaction
> effects between the 2 IV's. Am I on the right track? Any suggestions?
>
> Please give me your thoughts.
>
> Thanks,
> Debra Caywood-Rukas, M.Ed., Ed. S, NCSP
> Educational-School Psychologist