score.multiple.choice {psych} R Documentation

## Score multiple choice items and provide basic test statistics

### Description

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.

### Usage

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


### Arguments

 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 missing=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 skew Should the skews and kurtosi of the raw data be reported? Defaults to FALSE because what is the meaning of skew for a multiple choice item?

### Details

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

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

The example data set is taken from the Synthetic Aperture Personality Assessment personality and ability test at https://www.sapa-project.org/.

### Value

 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

### Author(s)

William Revelle

score.items, omega

### Examples

data(psychTools::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,psychTools::iqitems)
#just convert the items to true or false
iq.tf <- score.multiple.choice(iq.keys,psychTools::iqitems,score=FALSE)
describe(iq.tf)  #compare to previous results



[Package psych version 2.3.6 ]