c.
What general underlying construct do you think each of these three items is measuring?
I think that these three items are measuring the confidence of people in certain government
factions.
d.
Let’s try constructing the Cronbach’s alpha.
This measure is a scale reliability
coefficient.
The higher the value the more consistently the three items scale together.
Generally values of greater than 0.6 or so are considered minimally acceptable while
values greater than 0.7 are considered good.
Use the following command
alpha
conpol congov conciv.
.
Paste the output into the output sheet
.
Do these measures
have an acceptably high scale reliability coefficient?
These measures do indeed have a high scale reliability coefficient of 0.7096.
PART 3:
Constructing the scale
Now let’s try constructing the scale.
The simplest way to do this is to use the gen command to
generate a new variable and set it equal to the sum of the three variables from which our scale is
to be composed.
We can do this quite simply:
gen conscale = conpol+congov+conciv.
This command tells stata to generate a new variable called
conscale
that is equal to the sum of
the values from
conpol, congov
and
conciv
.
Tab this new variable and
paste the output
into the output sheet
.
You might want to try listing the first ten observations of the scale and
the variables from which it is composed to get a sense of how this worked.
Now let’s try another version of an additive scale.
Rather than simply adding the scales together,
let’s construct a measure that consists of a count of the number of institutions in which the
respondent has confidence.
Run the following code in your dofile.
gen conscale2=0
replace conscale2=conscale2+1 if conpol>2
replace conscale2=conscale2+1 if congov>2
replace conscale2=conscale2+1 if conciv>2
What is this code doing?
How is it different than what we ran to generate the first
conscale
?
The code is replacing variables and showing the real changes made, so it is very different
compared to the fist conscale and generates more real change.
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 Spring '13
 JoeDiGrazia
 Sociology, Control key, output sheet

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