How (Method) To Calculate The Rank Order Correlation (inter-rater and intra-rater)

i.             Carry out a rank order correlation of the first and second sets of marks. 

       This is to check ‘intra-rater reliability’.
ii.            Correlate the first set of marks with another person’s first set of marks. 

       This is to check ‘inter-rater reliability’.

The formula

N: number of student

d: the difference of the rank

Sample of data tabulation

1. i.          Intra-rater reliability

	1st time		2nd time		d = R1-R2	d2
	Mark	Rank (R1)	Mark	Rank (R2)
Student 1
Student 2
Student 3
Student 4
Student 5

1. ii.        Inter-rater reliability

	Own 1st time		Other 1st time		d = R1-R0	d2
	Mark	Rank (R1)	Mark	Rank (R0)
Student 1
Student 2
Student 3
Student 4
Student 5

Check out these links for more detailed explanation:

https://statistics.laerd.com/statistical-guides/spearmans-rank-order-correlation-statistical-guide.php

http://www.wikihow.com/Calculate-Spearman's-Rank-Correlation-Coefficient