An analysis plan for mv_ask() — mv

A plan lists, in a structured form, what the generated script should do: which columns are items, which model to fit, which group to test for DIF and which outputs to produce. mv_ask() fills a plan from a plain-language request, but a plan can also be written by hand and passed to mv_ask(plan = ), or changed with update_plan().

Usage

mv_plan(
  items = NULL,
  model = "auto",
  nfact = 1,
  group = NULL,
  missing = NULL,
  key = NULL,
  rt = NULL,
  steps = c("describe", "fitcheck", "interpret"),
  options = list(),
  assumptions = character()
)

update_plan(plan, ...)

Arguments

items: item columns: a character vector of names, a range such as "Q1:Q20", or NULL for all columns that look like items.
model: "auto" (compare models with select_model()), "Rasch", "2PL", "3PL", "graded" or "gpcm".
nfact: number of latent dimensions (1 to 3).
group: name of a grouping column (e.g. "gender") for a DIF analysis. Setting it adds the "dif" step.
missing: numeric codes that mean "missing", e.g. c(9, 99).
key: answer key for multiple-choice items that are not yet scored.
rt: response-time columns, one per item and in the same order. Setting it adds the "rt" step.
steps: the analysis steps, any of "describe", "fitcheck", "dif", "scores", "plots", "interpret", "cards", "report" and "rt". A model is always fitted.
options: per-step options as a named list of lists, e.g. list(scores = list(method = "MAP", file = "scores.csv"), report = list(file = "report.html"), fit = list(criterion = "AIC")).
assumptions: notes about how the request was understood; they are printed with the plan and written as comments in the script.
plan: an mv_plan object.
...: fields to change, as in mv_plan().

Value

An object of class mv_plan.

Examples

mv_plan(model = "2PL", group = "gender", steps = c("fitcheck", "report"))
#> Analysis plan
#>   - Items: all columns that look like items 
#>   - Model: 2PL, 1 dimension 
#>   - DIF by: gender 
#>   - Steps: fit, fitcheck, dif, report