W5 Assignment 1: SPSS Training: Reliability Analysis

The goal of this exercise is to evaluate a measure of tolerance, where tolerance refers to the willingness to allow people to express opinions that might be very different from their own. You will be using Cronbach's Alpha to estimate the internal consistency or reliability of the variables that make up the tolerance measure.

Orientation to the Measure

We're going to use the General Social Survey (GSS) for this exercise. The GSS is a national probability sample of adults in the United States conducted by the National Opinion Research Center. The GSS started in 1972 and has been an annual or biannual survey ever since.For this exercise we're going to use a subset of the 2014 GSS.

Tolerance refers to the willingness of individuals to allow others to express opinions which might be very different from their own and to exercise their basic civil liberties in the expression of these opinions. The GSS has a series of 18 variables that we can use to measure tolerance. These 18 variables are divided into three sets of six variables each.

One set of variables deals with the willingness of respondents to allow those who might hold these very different opinions to teach in a college. The questions on which these variables are based start with a general statement that "there are always some people whose ideas are considered bad or dangerous by other people. For instance, somebody who is against all churches and religion."This statement is followed by a question - "Should such a person be allowed to teach in a college or university, or not?" There are six scenarios presented (with the corresponding variable abbreviations):

• "somebody who is against all churches and religion" [ATH];
• "a man who admits he is a communist" [COM];
• "a man who admits he is a homosexual" [HOMO];
• "a person who advocates doing away with elections and letting the military run the country" [MIL];
• "a Muslim clergyman who preaches hatred of the United States" [MSLM]; and
• "a person who believes that Blacks are inferior" [RAC].

The second set of questions focus on these same six scenarios but ask whether a book that such a person wrote "should be taken out of your public library." The third set asks whether such a person should "be allowed to make a speech in your (city/town/community)."

Some information about the history of these items: These questions were originally developed by Samuel Stouffer in his book Communism, Conformity, and Civil Liberties (Doubleday, 1955). He asked about teaching in a college or university, having a book in a public library, and making a public speech for three groups:

• Communists,
• socialists, and
• those against all churches and religions.

These nine questions were included in the first three General Social Surveys in 1972, 1973, and 1974. The question about socialists was dropped in 1975 and a question about homosexuals was added in 1973, those advocating military control of the country and those who are racists in 1976, and Muslim clergyman who preach hatred of the United States in 2008. (See Tom W. Smith, "A Review of the Stouffer Civil Liberties Items on the General Social Survey," GSS Topical Report No. 42, 2009) The wording of the questions was not changed over time to ensure the comparability of the questions. While we might prefer to bring the wording of the questions more in line with the way we would ask them today, it's more important to maintain continuity over time.

So, we're working with 18 variables which are listed below:

• six questions focusing on teaching in a college or university - variable names are T1_COLATH, T2_COLCOM, T3_COLHOMO, T4_COLMIL, T5_COLMSLM, T6_COLRAC;
• six questions focusing on having books in a public library - variable names are T7_LIBATH, T8_LIBCOM, T9_LIBHOMO, T10_LIBMIL, T11_LIBMSLM, T12_LIBRAC; and
• six questions focusing on making a public speech in their community - variable names are T13_SPKATH, T14_SPKCOM, T15_SPKHOMO, T16_SPKMIL, T17_SPKMSLM, T18_SPKRAC.

Analyzing Reliability

Each group being asked about has three variables that apply to it: COL (teach in a college), LIB (have books in a library), and SPK (give a public speech). We need to determine if these three variables are internally consistent. This is basically a question of reliability. Are they consistent in the sense that a person who agrees that someone who is against religion should be allowed to teach in a college also thinks that such a person should also be allowed to make a public speech and have their books in public libraries?

Use SPSS to compute Cronbach's Alpha for the three questions about those who are opposed to religion. Those are T1_COLATH, T7_LIBATH, T13_SPKATH. Open the data set in SPSS and click on "Analyze" in the menu.Then point your mouse at "Scale" and click on "Reliability Analysis". Click on each of the three variables in the box on the left and move them over to the "Item" box on the right until you have selected all three variables. Click on the "Statistics" button in the upper right. This will open the Statistics box. Then click on "Scale if item deleted" in the upper left and "Correlations" in the upper right. Click on "Continue" and this will take you back to the original box where you selected the variables. Finally click on "OK" and SPSS will carry out the calculations you requested. See the video and tutorials in this week's readings and resources if you need additional help completing these analyses.

In your output there are three important pieces of information:

• the value of Cronbach's Alpha,
• the inter-item correlation matrix showing the correlations between each pair of variables, and
• the value of Cronbach's Alpha if an item (i.e., variable) is deleted.

You want to get a Cronbach's Alpha of .70 or higher. The correlations between variables should be consistently high. Generally the higher the inter-item correlations, the higher the value of Alpha.It's also helpful to look at the effect of deleting a variable on Alpha. This will tell you if you ought to consider deleting that variable.

Assignment

1. Follow the above instructions to compute Cronbach's alpha for each of the six groups (you are essentially treating these like six separate scales, three questions each). Complete the table below with your results.

Group	Cronbach's alpha
Those who are opposed to religion
Communists
"Homosexuals"
Militarists
Anti-American Muslim clergyman
Racists

1. Based on your analysis, do you think that each of these composite measures is internally consistent or reliable? Using your results, explain why.

1. Indicate if any of the scales would be improved if a variable is deleted - how do you know?