Reverse Code Variables

Reverse codes numeric variables, commonly used for Likert scales where some items are negatively worded. Uses the formula: reversed = (max + min) - original.

Usage

reverse_code(data, Vars, min = NULL, max = NULL, suffix = "_r")

Arguments

data

A data frame.

Vars

Character vector of variable names to reverse code.

min

Numeric. Minimum value of the scale. If NULL (default), detected from data.

max

Numeric. Maximum value of the scale. If NULL (default), detected from data.

suffix

Character. Suffix for new column names. Default "_r".

Value

Data frame with reverse coded variables added.

Details

The reverse coding formula is: reversed = (max + min) - original

For a 1-5 Likert scale:

• 1 becomes 5

• 2 becomes 4

• 3 stays 3

• 4 becomes 2

• 5 becomes 1

If min/max are not specified, they are detected from the data. For Likert scales, it's recommended to explicitly specify min and max to ensure correct reversal even if extreme values are not present in the data.

Examples

if (FALSE) { # \dontrun{
# Create sample Likert data
df <- data.frame(
  item1 = c(1, 2, 3, 4, 5),
  item2 = c(5, 4, 3, 2, 1),  # reverse-worded
  item3 = c(2, 3, 4, 3, 2)
)

# Reverse code with automatic detection
df <- reverse_code(df, Vars = "item2")

# Reverse code with explicit scale (1-5 Likert)
df <- reverse_code(df, Vars = "item2", min = 1, max = 5)

# Reverse code multiple items
df <- reverse_code(df, Vars = c("item2", "item3"), min = 1, max = 5)

# 0-10 scale
df <- reverse_code(df, Vars = "item2", min = 0, max = 10)
} # }