Understanding How to Create Custom Color Schemes for Likert Scales in R's HH Package

Understanding the Likert Scale in R’s HH Package

Overview of the Problem

The HH package in R is a versatile tool for visualizing and analyzing multiple-choice survey data. One common type of data that can be represented with this package is the Likert scale, which is commonly used to measure attitudes or opinions on a range of topics. The problem at hand involves assigning colors to the responses based on user-defined categories.

In this article, we’ll delve into how to create custom color schemes for the Likert scale using R’s HH package and explore some key concepts along the way.

Introduction to the HH Package

The HH package is an extension of R that provides tools for visualizing and analyzing multiple-choice survey data. The package includes functions such as likertColor(), which generates colors based on user-defined characteristics, allowing users to create their own unique color schemes for different categories of responses.

Installing the HH Package

Before we can use the HH package in our analysis, we need to install it first.

# Install the HH package using CRAN
install.packages("HH")

# Alternatively, you can install it from a local repository (if available)

Creating Custom Color Schemes with likertColor()

The likertColor() function is the core tool for generating colors in the HH package. This function takes two main arguments:

  • nc: The number of categories.
  • ReferenceZero: A reference point to which all other values are relative.

By default, ReferenceZero is set to 5 (the middle value). However, you can adjust this parameter based on your specific needs.

Using likertColor() with Hex Codes

One way to generate custom colors for the Likert scale is by using hex codes. The following code snippet demonstrates how to do this:

# Load the HH package
library(HH)

# Define the color scheme
myColor <- c(
    "#E94E1B",  # Strongly Disagree
    "#F7AA4E",  # Disagree
    "#BEBEBE",   # Neutral
    "#6193CE",   # Agree
    "#00508C"     # Strongly Agree
)

# Create the Likert scale plot using the custom color scheme
plot.likert(resp, as.percent = TRUE, col = myColor)

Using likertColor() with Ordered Factors

Another way to generate colors for the Likert scale is by using ordered factors. The following code snippet demonstrates how to do this:

# Load the HH package
library(HH)

# Create an ordered factor with levels
orderedFactor <- factor(resp[, 1], levels = c("Missing", "Not Applicable", 
                                               "Strongly Disagree", "Disagree", 
                                               "Neutral", "Agree", "Strongly Agree"))

# Define the color scheme
myColor <- likertColor(nc = 7, ReferenceZero = 5)

# Create the Likert scale plot using the custom color scheme
plot.likert(resp, as.percent = TRUE, col = myColor)

Understanding Color Spaces

When working with colors in R’s HH package, it’s essential to understand the underlying color spaces used by the package.

The likertColor() function uses the HSV (Hue, Saturation, Value) color model by default. The HSV color model is particularly useful for tasks like color mapping and visualization, where certain characteristics of a value are emphasized more than others.

However, when working with hex codes, R’s display defaults to the RGB (Red, Green, Blue) color space.

Understanding Hex Codes

Hex codes are used to represent colors in the HTML color model. They consist of six hexadecimal digits that specify the intensity of each primary color channel: red, green, and blue.

Here’s a brief explanation of how hex codes work:

  • The first two digits (e.g., #E9) represent the amount of red present in the color.
  • The next two digits (e.g., 94) represent the amount of green present in the color.
  • The final two digits (e.g., E1) represent the amount of blue present in the color.

By combining different intensities of these primary colors, you can create a vast range of colors and shades.

Advanced Color Mapping Techniques

While using hex codes and ordered factors is an effective way to generate custom colors for the Likert scale, there are even more advanced techniques that can help you further customize your visualization.

Here’s how you can apply multiple color mappings to different categories:

# Load the HH package
library(HH)

# Define a list of color schemes
colorSchemes <- list(
    Missing = "#E9E4E2",  # Light Grey
    NotApplicable = "#969696",  # Grey
    StronglyDisagree = "#B71C1C",  # Reddish Brown
    Disagree = "#B34D57",  # Earthy Red-Brown
    Neutral = "#FFD7BE",  # Warm Beige
    Agree = "#8BCDE0",  # Pastel Blue
    StronglyAgree = "#2196F3"  # Deep Navy Blue
)

# Apply the custom color scheme to each category
plot.likert(resp, as.percent = TRUE, col = function(x) {
    if (x == "Missing") return(colorSchemes$Missing)
    else if (x == "Not Applicable") return(colorSchemes$NotApplicable)
    else if (x == "Strongly Disagree") return(colorSchemes$StronglyDisagree)
    else if (x == "Disagree") return(colorSchemes$Disagree)
    else if (x == "Neutral") return(colorSchemes$Neutral)
    else if (x == "Agree") return(colorSchemes$Agree)
    else return(colorSchemes$StronglyAgree)
})

Best Practices for Custom Color Schemes

When creating custom color schemes, it’s essential to follow some best practices:

  • Consistency: Ensure that your colors are consistent with each other. Choose a dominant color scheme and use variations of those colors throughout your visualization.
  • Contrast: Make sure the contrast between different categories is sufficient for clear differentiation.
  • Accessibility: Consider accessibility when selecting colors, as some colors may not be easily visible or readable by all individuals.

By following these best practices, you can create visually appealing and informative custom color schemes that effectively communicate your message to your audience.

Conclusion

In conclusion, creating custom color schemes is an essential part of data visualization. By understanding the basics of color spaces, hex codes, and advanced mapping techniques, you can create visually appealing and informative visualizations that effectively communicate your message to your audience.


Last modified on 2025-03-07