How to Calculate Polychoric Correlation in R?

In this article, we will discuss how to calculate polychoric correlation in R Programming Language.

Calculate Polychoric Correlation in R

Correlation measures the relationship between two variables. we can say the correlation is positive if the value is 1, the correlation is negative if the value is -1, else 0. Polychoric correlation is used to calculate the correlation between ordinal variables. It is similar to actual correlation conditions. We can calculate it by using polychor() method. It is available in polychor library so we need to import it.

Syntax: polychor(data1,data2)

where, data is the two input data

Example 1: Calculate  polychoric correlation in two vectors

In this example, we will Calculate Polychoric Correlation between two vectors

# load the library
library(polycor)

# define two vectors
data1 = c(1, 2, 1, 2, 3, 4, 2, 3, 4, 5, 6)
data2 = c(1, 2, 1, 2, 3, 6, 7, 8, 6, 5, 5)

# calculate polychoric correlation 
# between two data
polychor(data1, data2)

Output:

[1] 0.5673752

Example 2: Calculate polychoric correlation in two columns of the dataframe

# load the library
library(polycor)

# define dataframe with 2 columns
data = data.frame( data1=c(1, 2,1,2,3,4,2),
                  data2= c(3,6,7,8,6,5,5))

# calculate polychoric correlation between
# two columns
polychor(data$data1,data$data2)

Output:

[1] 0.02894605