Dear Professor Revelle and R-helpers,
This is a two-part question: the first part is general, and the second
is specific to the psych package.
First question: In the past I've constructed composite variables from
questionnaire data by using rowMeans(), and then correlating items
with the scale
...@northwestern.edu
Cc: r-help@r-project.org
Subject: [R] reliability, scale scores in the psych package
Dear Professor Revelle and R-helpers,
This is a two-part question: the first part is general, and
the second is specific to the psych package.
First question: In the past I've constructed composite
snip
Second question: I spent some time with the psych package trying to
figure out how to use the score.items() function, and it's become
clear to me that I don't understand what it's doing. I assumed that
setting a key equal to -1 would result in the item being reverse
scored, but I get
Doran, Harold HDoran at air.org writes:
Ista
There are several functions in the MiscPsycho package that can be sued
for classical item analysis.
Since when is classical item analysis a crime?
No wonder the USA is considered such a litigious society!
Ken
--
Ken Knoblauch
Inserm U846
Ista,
As you figured out, psych reverses items by subtracting from the
maximimum + minimum possible for each item. (i.e., for items going
from 1 to 4, it reverses items by subtracting from 5).
If all of the items have the same potential range then you can just
let it figure out the
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