library(contentanalysis)
# Import document
doc <- pdf2txt_auto("paper.pdf", n_columns = 2)
# Calculate readability for full text
readability <- calculate_readability_indices(
doc$Full_text,
detailed = FALSE
)
print(readability)Readability Metrics
Overview
The calculate_readability_indices() function calculates various readability metrics to assess text complexity and accessibility. These metrics are valuable for evaluating scientific writing quality and comparing sections of academic papers.
Main Function
calculate_readability_indices()
Calculate multiple readability indices for text.
Usage
calculate_readability_indices(
text,
detailed = FALSE
)Arguments
text: Character string containing the text to analyzedetailed: Logical. If TRUE, returns additional metrics and detailed statistics
Value
A data frame containing:
Basic metrics (always returned): - flesch_reading_ease: Flesch Reading Ease (0-100, higher = easier) - flesch_kincaid_grade: Flesch-Kincaid Grade Level - gunning_fog: Gunning Fog Index - smog: SMOG (Simple Measure of Gobbledygook) Index - automated_readability: Automated Readability Index (ARI)
Additional metrics (if detailed = TRUE): - Word count statistics - Sentence statistics - Syllable counts - Complex word percentages
Basic Usage
Single Text Analysis
Example output:
flesch_reading_ease flesch_kincaid_grade gunning_fog smog automated_readability
1 38.2 15.7 17.3 14.8 16.2
Detailed Analysis
# Get detailed metrics
readability_detailed <- calculate_readability_indices(
doc$Full_text,
detailed = TRUE
)
print(readability_detailed)
# Additional metrics include:
# - total_words
# - total_sentences
# - total_syllables
# - avg_words_per_sentence
# - avg_syllables_per_word
# - complex_word_count
# - complex_word_percentageUnderstanding Metrics
Flesch Reading Ease
Scale: 0-100 (higher scores = easier to read)
- 90-100: Very Easy (5th grade)
- 80-90: Easy (6th grade)
- 70-80: Fairly Easy (7th grade)
- 60-70: Standard (8th-9th grade)
- 50-60: Fairly Difficult (10th-12th grade)
- 30-50: Difficult (College)
- 0-30: Very Difficult (College graduate)
# Interpret Flesch Reading Ease
interpret_flesch <- function(score) {
if (score >= 90) "Very Easy"
else if (score >= 80) "Easy"
else if (score >= 70) "Fairly Easy"
else if (score >= 60) "Standard"
else if (score >= 50) "Fairly Difficult"
else if (score >= 30) "Difficult"
else "Very Difficult"
}
score <- readability$flesch_reading_ease
cat("Reading ease:", score, "-", interpret_flesch(score), "\n")Flesch-Kincaid Grade Level
Indicates the U.S. grade level needed to understand the text.
grade <- readability$flesch_kincaid_grade
cat("Grade level required:", round(grade, 1), "\n")
if (grade < 8) {
cat("Accessible to middle school students\n")
} else if (grade < 12) {
cat("High school reading level\n")
} else if (grade < 16) {
cat("College undergraduate level\n")
} else {
cat("Graduate-level reading difficulty\n")
}Other Indices
Gunning Fog Index - Estimates years of formal education needed - Similar interpretation to Flesch-Kincaid
SMOG Index - Based on complex words (3+ syllables) - Conservative estimate of reading grade
Automated Readability Index (ARI) - Based on character counts - Corresponds to U.S. grade levels
Section Comparison
Compare All Sections
# Calculate readability for each section
sections_to_analyze <- c("Abstract", "Introduction", "Methods",
"Results", "Discussion")
readability_by_section <- data.frame()
for (section in sections_to_analyze) {
if (section %in% names(doc)) {
metrics <- calculate_readability_indices(doc[[section]], detailed = TRUE)
metrics$section <- section
readability_by_section <- rbind(readability_by_section, metrics)
}
}
# View results
print(readability_by_section)Visualization
library(ggplot2)
library(tidyr)
# Prepare data for plotting
plot_data <- readability_by_section %>%
select(section, flesch_reading_ease, flesch_kincaid_grade,
gunning_fog, smog, automated_readability) %>%
pivot_longer(cols = -section, names_to = "metric", values_to = "value")
# Create faceted plot
ggplot(plot_data, aes(x = section, y = value, fill = section)) +
geom_col(show.legend = FALSE) +
facet_wrap(~metric, scales = "free_y") +
labs(title = "Readability Metrics by Section",
x = "Section", y = "Score") +
theme_minimal() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
# Compare Flesch Reading Ease across sections
ggplot(readability_by_section,
aes(x = reorder(section, flesch_reading_ease),
y = flesch_reading_ease, fill = section)) +
geom_col(show.legend = FALSE) +
coord_flip() +
labs(title = "Flesch Reading Ease by Section",
subtitle = "Higher scores indicate easier readability",
x = "Section", y = "Flesch Reading Ease") +
theme_minimal()Statistical Comparison
library(dplyr)
# Summary statistics
summary_stats <- readability_by_section %>%
summarise(
avg_ease = mean(flesch_reading_ease),
avg_grade = mean(flesch_kincaid_grade),
most_difficult = section[which.min(flesch_reading_ease)],
easiest = section[which.max(flesch_reading_ease)]
)
print(summary_stats)
# Section rankings
rankings <- readability_by_section %>%
select(section, flesch_reading_ease, flesch_kincaid_grade) %>%
arrange(desc(flesch_reading_ease))
cat("\nSections ranked by readability (easiest to hardest):\n")
print(rankings)Advanced Analysis
Word Complexity Analysis
# Analyze word complexity if detailed = TRUE
detailed_metrics <- readability_by_section %>%
select(section, avg_words_per_sentence, avg_syllables_per_word,
complex_word_percentage)
print(detailed_metrics)
# Visualize complexity components
ggplot(detailed_metrics,
aes(x = avg_words_per_sentence, y = complex_word_percentage,
color = section, size = avg_syllables_per_word)) +
geom_point(alpha = 0.7) +
labs(title = "Text Complexity Components",
x = "Average Words per Sentence",
y = "Complex Word Percentage (%)",
size = "Avg Syllables per Word") +
theme_minimal()Sentence Length Analysis
# Compare sentence lengths across sections
sentence_analysis <- readability_by_section %>%
select(section, total_sentences, total_words, avg_words_per_sentence) %>%
arrange(desc(avg_words_per_sentence))
print(sentence_analysis)
# Identify verbose sections
verbose_threshold <- mean(sentence_analysis$avg_words_per_sentence) +
sd(sentence_analysis$avg_words_per_sentence)
verbose_sections <- sentence_analysis %>%
filter(avg_words_per_sentence > verbose_threshold)
if (nrow(verbose_sections) > 0) {
cat("\nVerbose sections (long sentences):\n")
print(verbose_sections)
}Time-Series Analysis
Track readability across document segments:
# Divide document into segments
n_segments <- 20
full_text <- doc$Full_text
text_length <- nchar(full_text)
segment_size <- text_length / n_segments
segment_readability <- data.frame()
for (i in 1:n_segments) {
start_pos <- (i - 1) * segment_size + 1
end_pos <- min(i * segment_size, text_length)
segment_text <- substr(full_text, start_pos, end_pos)
metrics <- calculate_readability_indices(segment_text, detailed = FALSE)
metrics$segment <- i
segment_readability <- rbind(segment_readability, metrics)
}
# Plot trend
ggplot(segment_readability, aes(x = segment, y = flesch_reading_ease)) +
geom_line(color = "steelblue", size = 1) +
geom_point(color = "steelblue", size = 2) +
geom_smooth(method = "loess", se = TRUE, alpha = 0.2) +
labs(title = "Readability Throughout Document",
x = "Document Segment", y = "Flesch Reading Ease") +
theme_minimal()Comparative Studies
Compare Multiple Papers
# Analyze multiple papers
papers <- c("paper1.pdf", "paper2.pdf", "paper3.pdf")
paper_names <- c("Paper A", "Paper B", "Paper C")
comparison <- data.frame()
for (i in seq_along(papers)) {
doc <- pdf2txt_auto(papers[i], n_columns = 2)
metrics <- calculate_readability_indices(doc$Full_text, detailed = TRUE)
metrics$paper <- paper_names[i]
comparison <- rbind(comparison, metrics)
}
# Compare papers
print(comparison)
# Visualize
ggplot(comparison, aes(x = paper, y = flesch_reading_ease, fill = paper)) +
geom_col(show.legend = FALSE) +
labs(title = "Readability Comparison Across Papers",
x = "Paper", y = "Flesch Reading Ease") +
theme_minimal()Benchmarking
Compare against discipline standards:
# Define discipline benchmarks (example values)
benchmarks <- data.frame(
discipline = c("Medicine", "Computer Science", "Social Sciences",
"Humanities", "Natural Sciences"),
typical_fre = c(35, 42, 48, 52, 38),
typical_fkg = c(16, 14, 13, 12, 15)
)
# Compare paper to benchmarks
paper_metrics <- calculate_readability_indices(doc$Full_text)
paper_fre <- paper_metrics$flesch_reading_ease
paper_fkg <- paper_metrics$flesch_kincaid_grade
# Find closest discipline
benchmarks$fre_diff <- abs(benchmarks$typical_fre - paper_fre)
closest <- benchmarks[which.min(benchmarks$fre_diff), ]
cat("Your paper's readability is closest to:", closest$discipline, "\n")
cat("Your FRE:", paper_fre, "vs typical:", closest$typical_fre, "\n")Export Readability Data
# Create export directory
dir.create("readability_analysis", showWarnings = FALSE)
# 1. Section readability
write.csv(readability_by_section,
"readability_analysis/section_readability.csv",
row.names = FALSE)
# 2. Segment readability (if calculated)
if (exists("segment_readability")) {
write.csv(segment_readability,
"readability_analysis/segment_readability.csv",
row.names = FALSE)
}
# 3. Summary report
summary_report <- data.frame(
metric = c("Overall Flesch Reading Ease",
"Overall Grade Level",
"Most Readable Section",
"Least Readable Section"),
value = c(
readability$flesch_reading_ease,
readability$flesch_kincaid_grade,
summary_stats$easiest,
summary_stats$most_difficult
)
)
write.csv(summary_report,
"readability_analysis/summary_report.csv",
row.names = FALSE)Interpretation Guidelines
Academic Writing Standards
# Evaluate against academic standards
evaluate_academic_readability <- function(fre, fkg) {
cat("\n=== Readability Assessment ===\n\n")
# Flesch Reading Ease
cat("Flesch Reading Ease:", round(fre, 1), "\n")
if (fre < 30) {
cat("✓ Appropriate for academic/professional audience\n")
} else if (fre < 50) {
cat("✓ Standard academic difficulty\n")
} else {
cat("⚠ May be too simple for academic publication\n")
}
# Grade Level
cat("\nGrade Level:", round(fkg, 1), "\n")
if (fkg >= 14) {
cat("✓ College/graduate level appropriate\n")
} else if (fkg >= 12) {
cat("~ Upper undergraduate level\n")
} else {
cat("⚠ Below typical academic standard\n")
}
# Recommendations
cat("\nRecommendations:\n")
if (fre > 50) {
cat("- Consider using more technical vocabulary\n")
cat("- Increase sentence complexity where appropriate\n")
}
if (fkg < 12) {
cat("- Add more complex sentence structures\n")
cat("- Incorporate domain-specific terminology\n")
}
if (fre < 25 || fkg > 18) {
cat("- Consider breaking up very long sentences\n")
cat("- Ensure clarity is not sacrificed for complexity\n")
}
}
# Apply to your document
metrics <- calculate_readability_indices(doc$Full_text)
evaluate_academic_readability(metrics$flesch_reading_ease,
metrics$flesch_kincaid_grade)Tips and Best Practices
- Context matters: Technical papers naturally score lower
- Section differences: Methods often harder than Discussion
- Audience consideration: Adjust expectations by field
- Balance: Clarity vs. necessary complexity
To improve scores while maintaining rigor:
- Break long sentences into shorter ones
- Use active voice when possible
- Define technical terms clearly
- Vary sentence length and structure
- Use transitional phrases effectively
Typical academic papers:
- FRE: 30-50 (Difficult to Fairly Difficult)
- FK Grade: 13-16 (College to Graduate level)
- Gunning Fog: 14-18
Lower scores aren’t always better for academic writing!
See Also
- Text Analysis: Word frequency and n-grams
- Content Analysis: Comprehensive analysis
- Tutorial: Complete workflow examples