Reliability

Reliability It means the extent to which a test is consistent and dependable. It is concerned with the consistency of responses from moment to moment. However, it may not always be valid.
Techniques in Testing the Reliability of Assessment Methods or RAM
I. Test-retest Method The same test is administered twice to the same group of student and the correlation coefficient is determined.
Disadvantages:
1. When the time interval is short, the respondents may recall their previous responses resulting to high correlation coefficient or CC. 2. When the time interval is long, the students may forget or unlearn their responses resulting to a low correlation coefficient of the test . 3. Environmental condition such as noise, temperature, lighting etc. may affect the coefficient correlation. Spearman rank correlation coefficient or Spearman rho is used to measure the relationship between the first and second administered test given.

Where = Spearman rho,
D = Difference of 1st and 2nd test ranks N = Number of cases
Students
X
Y

1
15
16
6
4
2
4
2
16
15
5
5
0
0
3
12
11
9.5
9
.5
0.25
4
12
12
9.5
8
1.5
4.5
5
20
19
1
1
0
0

8.75

(moderate relationship)
Interpretation of Correlation Value
0
zero correlation
0.01 - 0.20 negligible correlation
0.21 - 0.40 low or slight correlation
0.41 - 0.70 moderate correlation
0.71 - 0.90 high correlation
0.91 - 0.99 very high correlation II. Parallel or Equivalent Method
The tests are administered to a group of students and the paired observation is correlated. To construct it, the contents, types of test, difficulty and instructions of administered tests should be similar but not identical. Pearson product-moment correlation coefficient is used to determine the correlation in this method.

Where = Pearson product moment
X = 1st test administered & Y= 2nd test administered

Student

1
20
20
400
400
400
2
16
17
256
289
272
3
17
15
289
225
255
4
12
12
144
144
144
5
18
17
324
289
306
TOTAL
83
81
1413
1347
1377
Given: