IMPACT: The Impact of Items
In IMPACT: The Impact of Items

Description Usage Arguments Details Value Author(s) References Examples

This function returns an estimation based on the patterns of items.

Introduce a set of categorical data set classifed as numerical data.

1	IMPACT(x, y)

`x`	is a data set
`y`	is a null value

This function returns a multivariate analysis of the impact of items to identify a bias in the questionnaire validation. It estimates the impact of items.

This funtion takes a set of values produced by the IMPACT. functions returns estimations for each item provided in the input x matrix.

Null.value a null value

Less.impact values of the item with less impact

Greater.impact values of the item with greater impact

Summary.table a summary table with the impact of items

Nery Sofia Huerta-Pacheco

Juniper, E. F., Guyatt, G. H., Streiner, D. L., & King, D. R. (1997). Clinical impact versus factor analysis for quality of life questionnaire construction. Journal of ClinicalEpidemiology, 233-238.

Allen, F., & Locker, D. (2002). A Modified Short Version of the Oral Health Impact Profile for Assessing Health-Related Quality of Life in Edentulous Adults. The International Journal of Prosthodontics, 15(5), 446-450.

Lesaffre, E. (2009). Statistical and methodological aspects of oral health research. John Wiley & Sons. DOI: 10.1002/9780470744116

Vicente Galindo, E. D. (2011). Analisis del Impacto frente a Teoria de Respuesta al Item (Trabajo Fin de Master). Master Universitario en Analisis Avanzado de Datos Multivariantes, Statistics Department, University of Salamanca, Spain.

## Not run: 
library(IMPACT)
##Reads a likert-type scale dataset
x<-matrix(c(2, 5, 5, 4, 4, 5, 4, 4, 5, 1, 3, 4, 4, 1, 5, 2, 2, 4, 3, 5,
5, 1, 1, 4, 5, 2, 2, 4, 4, 5, 2, 4, 2, 5, 3, 4, 3, 3, 5, 3,
3, 5, 5, 5, 5, 5, 5, 5, 5, 3, 4, 3, 5, 3, 4, 5, 4, 4, 4, 5,
4, 1, 2, 2, 3, 1, 1, 3, 2, 5, 3, 2, 1, 5, 2, 2, 4, 1, 5, 1,
2, 4, 4, 4, 3, 5, 5, 4, 2, 2, 4, 3, 5, 2, 4, 5, 4, 4, 1, 5,
4, 1, 2, 3, 3, 1, 2, 5, 4, 5, 4, 3, 1, 4, 1, 3, 4, 2, 4, 2,
4, 1, 2, 3, 4, 1, 1, 4, 4, 5, 3, 3, 1, 1, 1, 4, 4, 2, 4, 1,
5, 1, 3, 3, 4, 5, 3, 5, 4, 5, 4, 4, 2, 5, 2, 4, 4, 4, 4, 4,
4, 4, 2, 3, 1, 3, 2, 3, 3, 1, 1, 2, 4, 1, 5, 2, 2, 3, 3, 4),20,10)
##Put names of variables
colnames(x)<-c(paste("A","-",1:10))
##Declare a null value
y<-3
IMPACT(x,y)

## End(Not run)