What is a good type-token ratio?

TTR values range 0–1. A TTR of 0.5 means half the words are unique. Higher values indicate greater lexical diversity. Raw TTR decreases with text length, so corrected measures (D, vocd-D, MTLD) are preferred for comparing texts of different lengths.

MTLD (Measure of Textual Lexical Diversity) calculates the mean length of sequential word strings maintaining TTR ≥ 0.72. It is length-independent and is considered one of the most robust lexical diversity measures for second language assessment.

Type-Token Ratio (TTR) Lexical Diversity

Calculate the Type-Token Ratio TTR = unique word types / total word tokens as a measure of lexical diversity. Corrected TTR variants (CTTR, RTTR) adjust for text length. Used in linguistics, language assessment, and corpus analysis.

Data set — comma or newline separated

Statistical Results — n = 8

Count (n)8

Sum (Σx)40

Min2

Max9

Range7

Q14

Q35.5

IQR1.5

Mean (μ)5

Median4.5

Mode4

Pop. Variance (σ²)4

Pop. Std Dev (σ)2

Sample Variance (s²)4.571428571

Sample Std Dev (s)2.138089935

Skewness0.65625

Excess Kurtosis-0.21875

How to Use

Enter the values for the scenario you are assessing. Calculate the Type-Token Ratio TTR = unique word types / total word tokens as a measure of lexical diversity. Corrected TTR variants (CTTR, RTTR) adjust for text length. Used in linguistics, language assessment, and corpus analysis. Use the type-token ratio result to inform your calculation.

Type-Token Ratio (TTR) Lexical Diversity

How to Use

Frequently Asked Questions

What is a good type-token ratio?

What is MTLD?