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Reshape survey response data for conjoint analysis (single task set)

Source: R/reshape_projoint.R
reshape_projoint.Rd

Takes a wide survey data frame (e.g., from read_Qualtrics) and reshapes it so that each row corresponds to a single respondent–task–profile. Supports arbitrary ordering of base tasks and a single repeated task per respondent. The repeated base task is inferred from the first base outcome in .outcomes, and the repeated outcome must be the last element of .outcomes.

Usage

reshape_projoint(
  .dataframe,
  .outcomes,
  .choice_labels = c("A", "B"),
  .choice_map = NULL,
  .alphabet = "K",
  .idvar = "ResponseId",
  .repeated = TRUE,
  .flipped = TRUE,
  .covariates = NULL,
  .fill = FALSE,
  .allow_missing_choices = FALSE
)

Arguments

.dataframe

A data frame, preferably from read_Qualtrics.

.outcomes

Character vector of outcome column names in the asked order. If a repeated task is used, its outcome must be the last element.

.choice_labels

Character vector (default c("A","B")) giving the two labels that appear at the end of the outcome strings. Position defines profile identity: the first label means profile 1 and the second means profile 2. Ignored when .choice_map is supplied.

.choice_map

Optional named numeric vector that explicitly maps response values to Qualtrics profile positions, for example c("Community A" = 1, "Community B" = 2). The names should preferably be the complete strings stored in the outcome columns; shorter suffixes are also supported. The numbers refer to the profile positions encoded by columns such as K-1-1-* and K-1-2-*, not to new profile names. The vector must map exactly two unique labels to profiles 1 and 2. Verify the mapping against the survey instrument or QSF file because it cannot be inferred from the CSV alone.

.alphabet

Single character (default "K") indicating the Qualtrics prefix.

.idvar

Character (default "ResponseId") indicating the respondent id column.

.repeated

Logical (default TRUE) indicating whether a repeated task is present.

.flipped

Logical (default TRUE) indicating whether the repeated task flips profiles before agreement is computed.

.covariates

Optional character vector of respondent-level covariate column names to carry through.

.fill

Logical (default FALSE). If TRUE, fills agree within respondent across tasks as described under “Filling agreement”.

.allow_missing_choices

Logical (default FALSE). If FALSE, any missing outcome stops with an error. If TRUE, missing choices are retained as NA for both profiles in the affected task.

Value

A projoint_data object with elements $labels and $data; see Details.

Details

Scope and assumptions

  • One set of conjoint tasks with exactly two profiles per task (profiles 1 and 2).

  • For multi-set designs, call reshape_projoint() once per set and bind the results.

Expected input (Qualtrics K-codes)

  • Wide columns named K-<task>-<attribute> (attribute names) and K-<task>-<profile>-<attribute> (level names), with <task> in 1..n and <profile> in 1,2.

  • Rows with missing K-1-1 are dropped as empty tables (server hiccup safeguard).

Outcome columns (.outcomes)

  • List all choice variables in the order asked. If you include a repeated task, its outcome must be the last element.

  • For base tasks (all but the last element), the function extracts the base task id by reading the digits in each outcome name (e.g., "choice4", "Q4", "task04" -> task 4).

  • The set of base task ids extracted from .outcomes must exactly match the set of task ids present in the K-codes; otherwise an error is thrown.

  • The repeated base task is inferred as the digits in the first base outcome (i.e., the first element of .outcomes, excluding the final repeated outcome).

Choice parsing

  • The selected profile is parsed from the end of each outcome string and matched to .choice_labels or .choice_map. Matching is case-sensitive and uses the full supplied label, so multi-character labels are supported.

  • The package cannot infer whether a Qualtrics code or displayed label refers to profile 1 or profile 2. Analysts must verify that mapping from the survey instrument or QSF file. Use .choice_map to make the verified mapping explicit and auditable.

  • For clarity, use the complete response strings stored in the outcome columns as the names of .choice_map. Shorter suffixes are supported, but the supplied strings must match the ends of all non-missing outcome values exactly, including case and whitespace.

  • Unrecognized, ambiguous, or whitespace-altered choice values cause an error. Missing choices also cause an error unless .allow_missing_choices = TRUE is supplied explicitly.

Output

  • A projoint_data object with:

    • $labels: map from human-readable attribute/level to stable ids (attribute_id = "att1","att2",..., level_id = "attX:levelY").

    • $data: tibble with one row per id–task–profile, attribute columns (named att*) storing level_id, selected (1 if that profile was chosen; 0 otherwise), agree (1/0/NA for repeated-task agreement after flip logic), and any .covariates. id is coerced to character; attribute columns are factors.

Filling agreement

  • If .fill = TRUE, agree is filled within respondent across tasks in task order, propagating the observed repeated-task agreement to all tasks for that respondent. This assumes IRR is respondent-specific and independent of table content.

Diagnostics

  • dplyr::count(reshaped$data, task, profile) should show exactly two rows per task.

  • If pj_estimate() later reports “No rows match the specified attribute/level”, construct QoIs from reshaped$labels (use the exact attX:levelY ids).

See also

make_projoint_data, projoint

Examples

# \donttest{
# Base tasks asked in numeric order; repeated task corresponds to task 1
data(exampleData1)
outcomes <- c(paste0("choice", 1:8), "choice1_repeated_flipped")
reshaped <- reshape_projoint(
  exampleData1,
  outcomes,
  .choice_map = c("Community A" = 1, "Community B" = 2)
)
dplyr::count(reshaped$data, task, profile) # should be 2 per task
#> # A tibble: 16 × 3
#>     task profile     n
#>    <dbl>   <dbl> <int>
#>  1     1       1   400
#>  2     1       2   400
#>  3     2       1   400
#>  4     2       2   400
#>  5     3       1   400
#>  6     3       2   400
#>  7     4       1   400
#>  8     4       2   400
#>  9     5       1   400
#> 10     5       2   400
#> 11     6       1   400
#> 12     6       2   400
#> 13     7       1   400
#> 14     7       2   400
#> 15     8       1   400
#> 16     8       2   400
# }