Create number of items per test form constraints.

Creates constraints related to the number of items in each test form.

Usage

itemsPerFormConstraint(
  nForms,
  nItems = NULL,
  operator = c("<=", "=", ">="),
  targetValue,
  whichForms = seq_len(nForms),
  itemIDs = NULL
)

Arguments

nForms

Number of forms to be created.

nItems

Number of items in the item pool [optional to create itemIDs automatically].

operator

A character indicating which operator should be used in the constraints, with three possible values: "<=", "=", or ">=". See details for more information.

targetValue

The target value to be used in the constraints. That is, the number of items per form.

whichForms

An integer vector indicating which test forms should be constrained. Defaults to all the test forms.

itemIDs

a character vector of item IDs in correct ordering, or NULL.

Value

An object of class "constraint".

Details

The number of items per test form is constrained to be either (a) smaller or equal than (operator = "<="), (b) equal to (operator = "="), or (c) greater or equal than (operator = ">=") the chosen value.

Examples

## Constrain the test forms to have exactly five items
itemsPerFormConstraint(3, operator = "=", targetValue = 5,
                       itemIDs = 1:20)
#> $A_binary
#> 3 x 60 sparse Matrix of class "dgCMatrix"
#>                                                                               
#> [1,] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 . . . . . . . . . . . . . . . . .
#> [2,] . . . . . . . . . . . . . . . . . . . . 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
#> [3,] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
#>                                                   
#> [1,] . . . . . . . . . . . . . . . . . . . . . . .
#> [2,] 1 1 1 . . . . . . . . . . . . . . . . . . . .
#> [3,] . . . 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
#> 
#> $A_real
#> NULL
#> 
#> $operators
#> [1] "=" "=" "="
#> 
#> $d
#> [1] 5 5 5
#> 
#> $c_binary
#> NULL
#> 
#> $c_real
#> NULL
#> 
#> attr(,"class")
#> [1] "constraint"
#> attr(,"nForms")
#> [1] 3
#> attr(,"nItems")
#> [1] 20
#> attr(,"info")
#>   rowNr formNr itemNr     constraint
#> 1     1      1     NA itemsPerForm=5
#> 2     2      2     NA itemsPerForm=5
#> 3     3      3     NA itemsPerForm=5
#> attr(,"itemIDs")
#>  [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20