Description Usage Arguments Details Value See Also Examples

View source: R/bootstrap_sctest.R

`bootstrap_sctest`

computes score test to detect DIF in multiple
item/parameters with respect to multiple person covariates (`DIF_covariate`

).
To obtain the p-values a resampling approach is applied. That is, given the
(item and person) parameters, new data sets are sampled to create the
distribution of the test statistic under the null-hypothesis. The
functionality is limited to the 1-, 2-, and 3-parameter logistic models.
Only DIF with respect to the `a`

and `b`

parameters are tested for,
respectively the item discriminations and the item difficulties.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
bootstrap_sctest(
resp,
theta = NULL,
a = rep(1, length(b)),
b,
c = rep(0, length(b)),
DIF_covariate = NULL,
parameters = c("per_item", "ab", "a", "b"),
item_selection = NULL,
nSamples = 1000,
theta_method = c("wle", "mle", "eap", "map"),
slope_intercept = FALSE,
statistic = "auto",
meanCenter = TRUE,
decorrelate = FALSE,
impact_groups = rep(1, dim(resp)[1])
)
``` |

`resp` |
A matrix (or data frame) containing the responses, with the items in the columns. |

`theta` |
A vector with the true/estimated ability parameters or NULL (the default) which leads to the ability parameters being estimated. |

`a` |
A vector of item slopes/item discriminations. |

`b` |
A vector of item locations/item difficulties. |

`c` |
A vector of pseudo guessing parameters. |

`DIF_covariate` |
A list with the person covariate(s) to test for as element(s). |

`parameters` |
A character string, either "per_item", "ab", "a", or "b", to specify which parameters should be tested for. |

`item_selection` |
A character vector with the column names or an integer
vector with the column numbers in the |

`nSamples` |
An integer value with the number of permutations to be sampled. |

`theta_method` |
A character string, either "wle", "mle", "eap", of
"map" that specifies the estimator for the ability estimation. Only
relevant when |

`slope_intercept` |
A logical value indicating whether the slope-intercept formulation of the 2-/3-PL model should be used. |

`statistic` |
A character string, either "auto", "DM", "CvM", "maxLM", "LMuo", "WDMo", or "maxLMo", specifying the test statistic to be used. |

`meanCenter` |
A logical value: should the score contributions be mean centered per parameter? |

`decorrelate` |
A logical value: should the score contributions be decorrelated? |

`impact_groups` |
A vector indicating impact-group membership for each person. |

Author: Dries Debeer

a list with four elements:

`statistics`

A matrix containing all the test statistics.

`p`

A matrix containing the obtained

*p*-values.`nSamples`

The number of samples taken.

`DIF_covariate`

A list containing all the covariate(s) used to order the score contributions, as well as the used test statistics.

1 2 3 4 5 6 7 8 9 |

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