Consider the following results from a five-question attitude scale. Dichotomize the answers and calculate the 1) Minimal Marginal Reproducibility; 2) Coefficient of Reproducibility; 3) % improvement; and 4) Coefficient of Scalability. Is this a Unidimensional Scale? (PDF Example of Guttman Scale attached)
Q#1 | Q#2 | Q#3 | Q#4 | Q#5 |
+A | +A | A | +A | +A |
+A | A+ | A+ | +A | +A |
+A | +A | A | A | +A |
+A | +A | = | +A | A |
+A | A | D | A | A |
A | A | A | = | D |
+A | A | A | D | D |
A | D | A | A | D |
+A | +A | = | D | D |
+A | A | D | D | D |
A | D | D | A | D |
+A | D | D | D | A |
+A | A | D | D | +D |
A | A | D | D | D |
A | D | A | D | D |
D | A | D | D | D |
A | D | D | D | D |
D | A | D | D | D |
D | D | D | +D | +D |
+D | +D | +D | +D | +D |