item_split_half function

Split-Half Reliability

Compute various measures of internal consistencies for tests or item-scales of questionnaires.

item_split_half(x, digits = 3)

Arguments

• x: A matrix or a data frame.
• digits: Amount of digits for returned values.

Returns

A list with two elements: the split-half reliability splithalf

and the Spearman-Brown corrected split-half reliability spearmanbrown.

Details

This function calculates the split-half reliability for items in x, including the Spearman-Brown adjustment. Splitting is done by selecting odd versus even columns in x. A value closer to 1 indicates greater internal consistency.

Examples

data(mtcars)
x <- mtcars[, c("cyl", "gear", "carb", "hp")]
item_split_half(x)

References

• Spearman C. 1910. Correlation calculated from faulty data. British Journal of Psychology (3): 271-295. tools:::Rd_expr_doi("10.1111/j.2044-8295.1910.tb00206.x")
• Brown W. 1910. Some experimental results in the correlation of mental abilities. British Journal of Psychology (3): 296-322. tools:::Rd_expr_doi("10.1111/j.2044-8295.1910.tb00207.x")