Check that a Q-matrix follows the expected structure

The Q-matrix should be 1 row per item and 1 column per attribute, with an optional additional column to store item identifiers. Each value of the Q-matrix should be a 0 or 1 to indicate measurement of the attribute by the given item. clean_qmatrix() calls check_qmatrix() to verify the expected structure, and then performs additional data manipulation to provide standard conventions. See details for additional information.

Usage

check_qmatrix(
  x,
  identifier = NULL,
  arg = rlang::caller_arg(x),
  call = rlang::caller_env()
)

clean_qmatrix(
  x,
  identifier = NULL,
  arg = rlang::caller_arg(x),
  call = rlang::caller_env()
)

Arguments

x

The provided Q-matrix to check.

identifier

The provided item identifier, as a character string. If no item identifier is present, the value should be NULL (the default).

arg

The name of the argument.

call

The call stack.

Value

check_qmatrix returns the original Q-matrix (if the checks pass) as a tibble with one row per item.

clean_qmatrix returns a list with four elements:

• clean_qmatrix: The cleaned Q-matrix

• attribute_names: The real names of the attributes

• item_identifier: The real name of the item identifier

• item_names: The real names of the items

Details

In many instances, it's important to have standard conventions for a Q-matrix so that we know what to expect (e.g., item identifiers, attribute names). clean_qmatrix() provides this standardization. For the cleaned Q-matrix, item identifiers and item names are removed. Additionally, all attributes are renamed att1, att2, att3, etc. Finally, all columns are coerced to integer values.

To ensure downstream functions are able to identify the original (pre-cleaned) values, clean_qmatrix() returns a list that includes the cleaned Q-matrix, as well as metadata that includes look-ups from the original to cleaned values.

Examples

example_qmatrix <- tibble::tibble(item = paste0("item_", 1:5),
                                  att_1 = c(0, 0, 1, 1, 1),
                                  att_2 = c(1, 1, 1, 0, 0))
check_qmatrix(example_qmatrix, identifier = "item")
#> # A tibble: 5 × 3
#>   item   att_1 att_2
#>   <chr>  <int> <int>
#> 1 item_1     0     1
#> 2 item_2     0     1
#> 3 item_3     1     1
#> 4 item_4     1     0
#> 5 item_5     1     0
example_qmatrix <- tibble::tibble(item = paste0("item_", 1:5),
                                  att_1 = c(0, 0, 1, 1, 1),
                                  att_2 = c(1, 1, 1, 0, 0))
clean_qmatrix(example_qmatrix, identifier = "item")
#> $clean_qmatrix
#> # A tibble: 5 × 2
#>    att1  att2
#>   <int> <int>
#> 1     0     1
#> 2     0     1
#> 3     1     1
#> 4     1     0
#> 5     1     0
#> 
#> $attribute_names
#>  att_1  att_2 
#> "att1" "att2" 
#> 
#> $item_identifier
#> [1] "item"
#> 
#> $item_names
#> item_1 item_2 item_3 item_4 item_5 
#>      1      2      3      4      5 
#>