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Readability

The readability component adds the following readabiltiy metrics under the ._.readability attribute to Doc objects.

Note

Note, that the hyphenation module (Pyphen) does not support all languages. If the language is not supported, a warning will be raised and np.nan will be set as the value for metrics requiring hyphenation.

  • `Gunning-Fog <https://en.wikipedia.org/wiki/Gunning_fog_index>`__, is a readability index originally developed for English writing, but works for any language. The index estimates the years of formal education needed to understand the text on a first reading. A Gunning-Fog index of 12 requires the reading level of a U.S. high school senior (around 18 years old). The formula for calculating the index is:

    Grade level = 0.4 × (ASL + PHW)

    Where ASL is the average sentence length (total words / total sentences), and PHW is the percentage of hard words (words with three or more syllables).

    Note: requires hyphenation.

  • `SMOG <https://en.wikipedia.org/wiki/SMOG>`__, or Simple Measure of Gobbledygook, is a readability formula that estimates the years of education required to understand a piece of writing. It primarily focuses on the complexity of words, using the number of polysyllabic words in the text. The formula is:

    SMOG Index = 1.043 × √(30 × (hard words / n_sentences)) + 3.1291

    Note: requires hyphenation.

  • `Flesch reading ease <https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests#Flesch_reading_ease>`__, is a readability score that indicates how easy a text is to read. Higher scores indicate easier reading, while lower scores indicate more difficult reading. The score is calculated using the following formula:

    Flesch Reading Ease = 206.835 - (1.015 × ASL) - (84.6 × ASW)

    Where ASL is the average sentence length and ASW is the average number of syllables per word.

    Note: requires hyphenation.

  • `Flesch-Kincaid grade <https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests#Flesch%E2%80%93Kincaid_grade_level>`__, is a readability metric that estimates the grade level needed to comprehend a text. It is based on the average sentence length and average number of syllables per word. The formula is:

    Flesch-Kincaid Grade = 0.39 × (ASL) + 11.8 × (ASW) - 15.59

    Note: requires hyphenation.

  • `Automated readability index <https://en.wikipedia.org/wiki/Automated_readability_index>`__, is a readability test that calculates an approximate U.S. grade level needed to understand a text. It is based on the average number of characters per word and the average sentence length. The formula is:

    ARI = 4.71 × (n_chars / n_words) + 0.5 × (n_words / n_sentences) - 21.43

  • `Coleman-Liau index <https://en.wikipedia.org/wiki/Coleman%E2%80%93Liau_index>`___, is a readability test that estimates the U.S. grade level needed to understand a text. It is based on the average number of letters per 100 words and the average number of sentences per 100 words. The original formula is:

    CLI = 0.0588 × L - 0.296 × S - 15.8

    Where L is the average number of characters per 100 words and S is the average number of sentences per 100 words. In our implementation we average over the entire text instead of just 100 words.

  • `Lix <https://en.wikipedia.org/wiki/Lix_(readability_test)>`__, or Lesbarhetsindex, is a readability measure that calculates a readability score based on the average sentence length and the percentage of long words (more than six characters) in the text. The formula is:

    Lix = (n_words / n_sentences) + (n_long_words * 100) / n_words

  • `Rix <https://www.jstor.org/stable/40031755>`__, is a readability measure that estimates the difficulty of a text based on the proportion of long words (more than six characters) in the text. The formula is:

    Rix = (n_long_words / n_sentences)

Usage

import spacy
import textdescriptives as td
nlp = spacy.load("en_core_web_sm")
nlp.add_pipe("textdescriptives/readability")
doc = nlp("The world is changed. I feel it in the water. I feel it in the earth. I smell it in the air. Much that once was is lost, for none now live who remember it.")

# all attributes are stored as a dict in the ._.readability attribute
doc._.readability

# extract to dataframe
td.extract_df(doc)
  text flesch_reading_ease flesch_kincaid_grade smog gunning_fog automated_readability_index coleman_liau_index lix rix token_length_mean token_length_median token_length_std sentence_length_mean sentence_length_median sentence_length_std syllables_per_token_mean syllables_per_token_median syllables_per_token_std n_tokens n_unique_tokens proportion_unique_tokens n_characters n_sentences
0 The world is changed(...) 107.879 -0.0485714 5.68392 3.94286 -2.45429 -0.708571 12.7143 0.4 3.28571 3 1.54127 7 6 3.09839 1.08571 1 0.368117 35 23 0.657143 121 5

Component

.. autofunction:: textdescriptives.components.readability.create_readability_component