score.multiple.choice {psych}R Documentation

Score multiple choice items and provide basic test statistics


Ability tests are typically multiple choice with one right answer. score.multiple.choice takes a scoring key and a data matrix (or data.frame) and finds total or average number right for each participant. Basic test statistics (alpha, average r, item means, item-whole correlations) are also reported.


score.multiple.choice(key, data, score = TRUE, totals = FALSE, ilabels = NULL, missing = TRUE, impute = "median", digits = 2,short=TRUE)


key A vector of the correct item alternatives
data a matrix or data frame of items to be scored.
score score=FALSE, just convert to right (1) or wrong (0).
score=TRUE, find the totals or average scores and do item analysis
totals total=FALSE: find the average number correct
total=TRUE: find the total number correct
ilabels item labels
missing missing=TRUE: missing values are replaced with means or medians
mising=FALSE missing values are not scored
impute impute="median", replace missing items with the median score
impute="mean": replace missing values with the item mean
digits How many digits of output
short short=TRUE, just report the item statistics,
short=FALSE, report item statistics and subject scores as well


Basically combines score.items with a conversion from multiple choice to right/wrong.

The item-whole correlation is inflated because of item overlap.


scores Subject scores on one scale
missing Number of missing items for each subject
item.stats scoring key, response frequencies, item whole correlations, n subjects scored, mean, sd, skew, kurtosis and se for each item
alpha Cronbach's coefficient alpha
av.r Average interitem correlation


William Revelle

See Also

score.items, omega


iq.keys <- c(4,4,3,1,4,3,2,3,1,4,1,3,4,3)
#just convert the items to true or false <- score.multiple.choice(iq.keys,iqitems,score=FALSE)
describe(  #compare to previous results

[Package psych version 1.0-68 Index]