フレッシュ可読性

How the Flesch Reading Ease Score Works

The Flesch Reading Ease score is a widely used readability formula developed by Rudolf Flesch in the 1940s. It's designed to indicate how difficult a passage in English is to understand. The score ranges from 0 to 100, with higher scores indicating easier readability.

The formula for calculating the Flesch Reading Ease score is:

206.835 - (1.015 × ASL) - (84.6 × ASW)

Where:
ASL = Average Sentence Length (number of words divided by number of sentences)
ASW = Average Syllables per Word (number of syllables divided by number of words)

The score is interpreted as follows:

90-100: Very easy to read. Easily understood by an average 11-year-old student.
80-90: Easy to read. Conversational English for consumers.
70-80: Fairly easy to read.
60-70: Easily understood by 13- to 15-year-old students.
50-60: Fairly difficult to read.
30-50: Difficult to read, best understood by college graduates.
0-30: Very difficult to read, best understood by university graduates.

The Flesch Reading Ease score is widely used in various fields, including education, publishing, and content creation. It helps ensure that written material is appropriate for its intended audience, fostering better comprehension and engagement.