# biserial: Calculate biserial correlation In irt: Item Response Theory and Computerized Adaptive Testing Functions

 biserial R Documentation

## Calculate biserial correlation

### Description

Calculate biserial correlation

### Usage

```biserial(score, criterion, method = "default")
```

### Arguments

 `score` Item scores of each examinee for which biserial correlation will be calculated `criterion` Total score of each examinee `method` Type of the biserial correlation calculation method. "default"The most common way to calculate biserial correlation. "point-biserial"Calculate point-biserial correlation. "clemans-lord"Modified biserial correlation value based on Clemans (1958) and Lord (1962). "brogden"Modified biserial correlation value based on: Brogden (1949) "rank"Rank biserial correlation value based on Cureton (1968).

### Value

Biserial correlation value

Emre Gonulates

### References

Brogden, H. E. (1949). A new coefficient: Application to biserial correlation and to estimation of selective efficiency. Psychometrika, 14, 169-182.

Clemans, W. V. (1958) An index of item-criterion relationship. Educational and Psychological Measurement, 18, 167-172.

Cureton, E. E. (1968). Rank biserial correlation when ties are present. Educational and Psychological Measurement, 28, 77-79.

Kraemer, H. C. (1981). Modified biserial correlation coefficients. Psychometrika, 46(3), 275-282.

Lord, F. M. (1963). Biserial estimates of correlation. Psychometrika, 28, 81–85.

### Examples

```# The example is from Salkind, Rasmussen (2007) Encyclopedia of measurement
# and statistics, pages 94-97
score <- c(rep(0, 16), rep(1, 22))
total_score <- c(87, 90, 94, 94, 97, 103, 103, 104, 106, 108, 109, 109, 109,
112, 119, 132, 100, 103, 103, 106, 112, 113, 114, 114, 118,
119, 120, 120, 124, 133, 135, 135, 136, 141, 155, 157, 159,
162)
# Calculate biserial correlation
biserial(score, total_score)
# Calculate point-biserial correlation
biserial(score, total_score, method = "point-biserial")
# Calculate modified biserial correlation (based on Brogden (1949))
biserial(score, total_score, method = "brogden")
# Calculate modified biserial correlation (Clemans-Lord)
biserial(score, total_score, method = "clemans-lord")

```

irt documentation built on Nov. 10, 2022, 5:50 p.m.