# Structural Mapping for an IRTree Model

### Description

Expands a wide-form file of item responses to a long-form file supporting structural mappings among latent variables

### Usage

1 |

### Arguments

`mat` |
An integer matrix of IRT responses (columns represent items, rows represent respondents) |

`cmx` |
The mapping matrix. |

`items` |
A numeric vector with the column positions of all items
(measurement variables) in |

`endnode` |
A factor with the same length as |

`crossitem` |
A factor with the same length as |

### Value

A data frame with columns:

`person` |
a factor identifying the respondent; |

`item` |
a factor identifying the items; |

`exo1 to exoS` |
dummy variables identifying the internal nodes: these play the same role as |

`endnode` |
a factor identifying the end nodes and thus the endogeneous latent variables; |

`crossitem` |
a factor produced only for crossed designs, identifying the items that are crossed
with |

`value` |
the binary item responses. |

### Author(s)

Ivailo Partchev

### References

De Boeck, P. and Partchev, I. (2012).
IRTrees: Tree-Based Item Response Models of the GLMM Family,
*Journal of Statistical Software – Code Snippets*, **48**(1), 1–28.
http://www.jstatsoft.org/v48/c01/.

### See Also

`dendrify`

### Examples

1 2 3 |