Dear All,
I have now received a clarification related to a previous query I posted
on the list, but unfortunately I am still unable to grasp the
clarification, so any clarification of the clarification would be much
appreciated!
The data include repeated measures (five data points) of two slightly
different questionnaires, the YSR and the YASR, which I need to
standardise.
I have been advised to:
1. Use the raw scale scores from the first YSRs (at intake) completed by
participants as a basis for assigning standard scores with a mean = 100,
SD = 15 for each scale.
2. Do the same for all the first YASRs.
3. After you have used the first-completed forms to establish relations
between raw scale scores and standard scores, you can apply the standard
scores to the raw scores of the later-completed forms, as well as to the
first-completed forms.
My problem was understanding step 3.
The clarification is as follows:
You have to use means and sd for 1st testing on subsequent ones. Not use
T-scores. Use z scores based on just adding and computing local norms as
it were. and...
Because you want to analyze YSRs and YASRs for the same subjects, you need
to create your own standard scores for the YSRs and separately
for the YASRS. Each set of standard scores should have the same mean and
sd. To avoid the effects of repeated administration of the same form, I
suggested that you use only the first YSR and the first YASR completed by
each subject to provide the raw scores that you would then convert to
standard scores.
What I am struggling with is understanding how I can use the scores at
intake (raw scores and standard scores) to create standard scores at later
time points. Any advice would be much appreciated.
Thank you very much,
Ioanna
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