Powers Sumner Kearl Readability Calculator Online

Powers Sumner Kearl Readability Score

The Powers-Sumner-Kearl formula is a recalibration of the Flesch Reading Ease formula, created by linguists R.D. Powers, W.A. Sumner, and B.E. Kearl in 1958. Their research was published in the article "A Recalculation of Four Adult Readability Formulas" in the Journal of Educational Psychology.

The formula was designed to improve the accuracy of existing readability measures and is most appropriate for children between seven and ten years old (U.S. grades 2-4).

Powers Sumner Kearl Formula

PSK = 0.0778 × ASL + 4.55 × (syllables/words) - 2.2029

Where:

• ASL = Average Sentence Length (total words ÷ total sentences)
• syllables/words = Average syllables per word (total syllables ÷ total words)

Variations

The researchers created several variations by recalibrating different readability formulas:

1. PSK Variation of Flesch Reading Ease (most commonly used)
2. PSK Variation of Dale-Chall
3. PSK Variation of Gunning's Fog Index

Score Interpretation

The Powers-Sumner-Kearl score indicates reading difficulty:

• Lower scores = Easier to read (appropriate for younger readers)
• Higher scores = More difficult to read (requires advanced reading skills)

The score can be converted to approximate grade levels to help determine the appropriate audience for your text.

Target Audience

The Powers-Sumner-Kearl formula is specifically calibrated for:

• Elementary school readers (grades 2-4)
• Children aged 7-10 years
• Beginning to intermediate reading levels

Strengths

• Improved Accuracy: Recalibrated based on empirical data to improve predictions
• Simplified Calculation: Uses easily countable text features
• Research-Backed: Based on rigorous linguistic research from 1958
• Elementary Focus: Specifically tuned for young readers

Limitations

• Most accurate for elementary-level texts (grades 2-4)
• May be less accurate for advanced or specialized content
• Does not consider vocabulary difficulty or context
• Like most formulas, cannot measure conceptual difficulty

Use Cases

The Powers-Sumner-Kearl formula is ideal for:

• Children's Books: Evaluating age-appropriate content for elementary readers
• Educational Materials: Creating grade-appropriate learning materials
• ESL Content: Developing materials for beginning English learners
• Simplified Texts: Ensuring content is accessible to young readers

Further Reading

• The Powers-Sumner-Kearl Readability Formula – ReadabilityFormulas.com
• The Powers Sumner Kearl Readability Formula – Readable
• Powers-Sumner-Kearl Readability Formula – Originality.AI