In order to write a monitoring report on a project, I have to analyse a survey with 6 different groups of questions each measuring a different ability (in each group I have from 6 to 9 questions). The questions are on a Likert scale from 1 to 4 (1 a lot, 2 enough, 3 a little, 4 not at all).

Such a 4-point scale is not called a Likert scale.

*Likert scale* is the name of a measurement

instrument consisting of several Likert-type items, jointly measuring a construct.

If the term "Likert scale" popped up during the preparation of your study, then either it was

simply used incorrectly (as it happens in about 87% of studies), or it was actually meant to

express that the 6 to 9 items measuring some ability togehter form a Likert scale. In the latter

case, summing up the scores of the 6 to 9 items would be the ususal practice.

But you did tell nothing about where the items and the item groups came from, whether they

were simply made up, or maybe taken from literature, or something else. Therefore it is

not easy to know what to assume.

Karabiner at the end of his last post writes that with a 4-point scale I can't use T-test (could I ask you why?),

A 4-point rating scale is usually considered as having the ordinal level of measurement.

For t-test, you need an interval scale. But I would rather not recommend to perform

about 40 to 50 (?) pre-post comparisons with single items, regardless of whether

the t-test is used or the sign test. If you construct a scale out of the 6-9 items measuring

an ability, then this resulting scale is usually considered interval, and you can use

t-tests on them.

About the sign test, it makes sense to calculate the median or the mean or the total for each observation within each group of questions at time 0 and time 1 and then use the sign test to compare these 2 new variables?

Well, that is not quite how the sign test works. Basically, it just looks at the

positive and negative changes between t0 and t1. Why not let the software

do that for you.

With kind regards

Karabiner