`dgirt`

and `dgmrp`

make calls to `stan`

with
the Stan code and data for their respective models.

dgirt(shaped_data, ..., separate_t = FALSE, delta_tbar_prior_mean = 0.65,
delta_tbar_prior_sd = 0.25, innov_sd_delta_scale = 2.5,
innov_sd_theta_scale = 2.5, version = "2017_01_04",
hierarchical_model = TRUE, model = NULL)
dgmrp(shaped_data, ..., separate_t = FALSE, delta_tbar_prior_mean = 0.65,
delta_tbar_prior_sd = 0.25, innov_sd_delta_scale = 2.5,
innov_sd_theta_scale = 2.5, version = "2017_01_04_singleissue",
model = NULL)

## Arguments

shaped_data |
Output from `shape` . |

... |
Further arguments, passed to `stan` . |

separate_t |
Whether smoothing of estimates over time should be
disabled. Default `FALSE` . |

delta_tbar_prior_mean |
Prior mean for `delta_tbar` , the normal
weight on `theta_bar` in the previous period. Default `0.65` . |

delta_tbar_prior_sd |
Prior standard deviation for `delta_bar` .
Default `0.25` . |

innov_sd_delta_scale |
Prior scale for `sd_innov_delta` , the Cauchy
innovation standard deviation of `nu_geo` and `delta_gamma` .
Default `2.5` . |

innov_sd_theta_scale |
Prior scale for `sd_innov_theta` , the Cauchy
innovation standard deviation of `gamma` , `xi` , and if
`constant_item` is `FALSE` the item difficulty `diff` . Default
`2.5` . |

version |
The name of the dgo model to estimate, or the path to a
`.stan` file. Valid names for dgo models are "2017_01_04",
"2017_01_04_singleissue". Ignored if argument `model` is used. |

hierarchical_model |
Whether a hierarchical model should be used to
smooth the group IRT estimates. If set to FALSE, the model will return raw
group-IRT model estimates for each group. Default `TRUE` . |

model |
A Stan model object of class `stanmodel` to be used in
estimation. Specifying this argument avoids repeated model compilation. Note
that the Stan model object for a model fitted with `dgirt()` or
`dgmrp()` can be found in the the `stanmodel` slot of the resulting
`dgirt_fit` or `dgmrp_fit` object. |

## Value

A `dgo_fit-class`

object that extends
`stanfit-class`

.

## Details

The user will typically pass further arguments to `stan`

via the `...`

argument, at a minimum `iter`

and `cores`

.

By default `dgirt`

and `dgmrp`

override the
`stan`

default for its `pars`

argument to specify
typical parameters of interest. They also set `iter_r`

to `1L`

.

Important: the `dgirt`

model assumes consistent coding of the polarity
of item responses for identification.