create new variable from likert scale

[Doordarshini Heerah]

Hi
I have many likert scale responses from my survey in 3-4 different categories of subjects (e.g. environmental attitudes, general attitudes, certain behaviours, etc). I want to sort of reduce the information into variables, so that I can include them in a regression model.
Any suggestion will help.
Thanks

[Felix Bittmann]

Well, if multiple items measure the same constructs, you can use alpha

alpha var1 var2 var3, gen(construct)
help alpha

If you are not sure whether they load on the same constructs, you can run a factor analysis or PCA

help pca

Or you can include them unchanged easily using factor variable notation

regress y i.var1 i.var2

[Doordarshini Heerah]

Thanks a lot !

[Doordarshini Heerah]

Well, if multiple items measure the same constructs, you can use alpha

alpha var1 var2 var3, gen(construct)
help alpha

Hi sorry for asking seeking out help again.

i got a scale reliability coeff of 0.1870 but unsure how to interpret it? it seems I have a very low reliability coefficient...

alpha ipol pol pets inher tech, gen(construct)

Test scale = mean(unstandardized items)
Reversed item: pets

Average interitem covariance: .0934579
Number of items in the scale: 5
Scale reliability coefficient: 0.1870

[Felix Bittmann]

Yes this is very low, results below 0.6 are critical. This means that either the variables do not measure the same construct. But without knowing the data in depth I cannot give more detailed advice. I suggest proceeding with a PCA to check whether there are multiple dimensions in the items.

[Doordarshini Heerah]

Thanks

the variables represent interest (1=None at all, 2=A little, 3=A moderate amount, 4=A lot, 5=A great deal, 6=Don't Know):
ipol:international politics
pol:international politics
pets:pets
inher:leaving inheritance
tech:technology to improve lives

[Felix Bittmann]

First, make sure to set value 6 to a missing, otherwise the results will be quite useless (replace VAR = . if VAR == 6)
Second, I do not understand what construct you attempt to create. What is the common theme of politics and pets?