irt (version 0.1.1)

biserial: Calculate biserial correlation

Description

Calculate biserial correlation

Usage

biserial(score, total_score, type = "default")

Arguments

score

Item scores of each examinee for which biserial correlation will be calculated

total_score

Total score of each examinee

type

Type of the biserial correlation.

"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, H. E. (1949). Psychometrika, 14, 169<U+2013>182

"rank"

Rank biserial correlation value based on Cureton (1968).

Value

Biserial correlation value

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<U+2013>85.

Examples

# NOT RUN {
# 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, type = "point-biserial")
# Calculate modified biserial correlation (based on Brogden (1949))
biserial(score, total_score, type = "brogden")
# Calculate modified biserial correlation (Clemans-Lord)
biserial(score, total_score, type = "clemans-lord")

# }