orlando_itemf: Orlando's statistic In IRTpp: Estimating IRT Parameters using the IRT Methodology

Description

Calculate the values of the statistics S_x2 from Maria Orlando and David Thisen.

Usage

 `1` ```orlando_itemf(patterns, G, zita, model) ```

Arguments

 `patterns` matrix of patterns response, the frequency of each pattern and the latent traits. `G` number of quadrature points. `zita` matrix of estimations of the parameters of the items (discrimination, difficulty, guessing). `model` type of model ( "1PL", 2PL", "3PL" ).

Value

Orlando's statistic, degrees of freedom and p-value for each item.

Author(s)

SICS Research, National University of Colombia [email protected]

References

Orlando, M. & Thissen, D. (2000). Likelihood-based item fit indices for dichotomous item response theory models. Applied Psychological Measurement, 24, 50-64.

See Also

`z3_itemf`

Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19``` ```#Simulates a test and returns a list: test <- simulateTest() #the simulated data: data <- test\$test #model: mod=irtpp(dataset = data,model = "3PL") #Convert parameters to a matrix zz <- parameter.matrix(mod\$z,byrow = FALSE) #Estimating Latent Traits p_mat <- mod\$prob_mat trait <- individual.traits(model="3PL", itempars = zz,method = "EAP",dataset = data, probability_matrix = p_mat) #Z3 PERSONFIT-Statistic orlando_itemf(patterns = as.matrix(trait),G = 61,zita = mod\$z,model = "3PL") ```

IRTpp documentation built on May 29, 2017, 9:58 a.m.