score.multiple.choice {psych}  R Documentation 
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, itemwhole 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). 
totals 
total=FALSE: find the average number correct 
ilabels 
item labels 
missing 
missing=TRUE: missing values are replaced with means or medians 
impute 
impute="median", replace missing items with the median score

digits 
How many digits of output 
short 
short=TRUE, just report the item statistics, 
Basically combines score.items
with a conversion from multiple choice to right/wrong.
The itemwhole correlation is inflated because of item overlap.
The example data set is taken from the Synthetic Aperture Personality Assessment personality and ability test at http://test.personalityproject.org.
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
data(iqitems) iq.keys < c(4,4,4, 6,6,3,4,4, 5,2,2,4, 3,2,6,7) score.multiple.choice(iq.keys,iqitems) #just convert the items to true or false iq.tf < score.multiple.choice(iq.keys,iqitems,score=FALSE) describe(iq.tf) #compare to previous results