Before you can reshape or analyze your conjoint survey data, you
first need to import it into R. In
projoint, use the read_Qualtrics()
function to quickly read properly formatted Qualtrics files.
When exporting from Qualtrics:
⚡ If you skip selecting “Use choice text,” your conjoint data may fail to load properly!
read_Qualtrics()
read_Qualtrics() automatically removes the question-text
and ImportId metadata rows used by current Qualtrics
exports. It also recognizes legacy exports with only a question-text row
while preserving the original variable names and column order.
Or, if using an example bundled with projoint:
## # A tibble: 518 Ă— 218
## StartDate EndDate Status Progress
## <dttm> <dttm> <chr> <dbl>
## 1 2022-03-01 10:44:18 2022-03-01 10:44:43 IP Address 100
## 2 2022-03-01 10:44:06 2022-03-01 10:47:59 IP Address 100
## 3 2022-03-01 10:45:30 2022-03-01 10:49:03 IP Address 100
## 4 2022-03-01 10:52:18 2022-03-01 10:56:29 IP Address 100
## 5 2022-03-01 10:54:34 2022-03-01 10:57:30 IP Address 100
## 6 2022-03-01 10:56:51 2022-03-01 10:58:06 IP Address 100
## 7 2022-03-01 10:58:09 2022-03-01 11:00:45 IP Address 100
## 8 2022-03-01 11:01:43 2022-03-01 11:01:51 IP Address 100
## 9 2022-03-01 10:58:35 2022-03-01 11:03:44 IP Address 100
## 10 2022-03-01 11:00:14 2022-03-01 11:04:37 IP Address 100
## # ℹ 508 more rows
## # ℹ 214 more variables: `Duration (in seconds)` <dbl>, Finished <lgl>,
## # RecordedDate <dttm>, ResponseId <chr>, DistributionChannel <chr>,
## # UserLanguage <chr>, Q_RecaptchaScore <dbl>, Q1.2 <chr>, Q2.2 <chr>,
## # Q2.3 <chr>, Q2.4 <chr>, Q2.5 <chr>, Q2.6 <chr>, Q2.7 <chr>, Q2.8 <chr>,
## # Q2.9 <chr>, Q3.1 <chr>, Q4.2 <chr>, Q4.3 <chr>, Q4.4 <chr>, Q4.5 <chr>,
## # Q4.6 <chr>, Q4.7 <chr>, Q4.8 <chr>, Q4.9 <chr>, Q5.1 <chr>, Q6.1 <chr>, …
Preparing your data correctly is one of the most important steps in
conjoint analysis. Fortunately, the reshape_projoint()
function in projoint makes this easy.
Outcome naming & order (important)
- List
.outcomesin the order questions were asked.
- If you have a repeated task, its outcome must be the last element.
- For base tasks (all but last), the function reads the digits in each name as the task id (e.g.,
"choice4","Q4","task04"→ task 4).
- The repeated base task is inferred from the first base outcome’s digits. The repeated outcome itself need not contain digits—only its position (last) matters.
- Specify the two exported response values with
.choice_map. Its names are the response strings stored in the outcome columns, and its values are the corresponding Qualtrics profile positions (1or2). For example, use.choice_map = c("Community A" = 1, "Community B" = 2)when those are the exported choices and the instrument confirms that Community A is profile 1. projoint cannot infer this mapping from the CSV.- Invalid labels, trailing whitespace, and missing choices now stop with an informative error. Retain missing choices only after review by setting
.allow_missing_choices = TRUE.
First inspect the response values that actually appear in your outcome columns. For example:
## [1] "Community A" "Community B"
Then verify the relationship between those response values and the two profile positions using the Qualtrics instrument or QSF file. Write the verified relationship as:
.choice_map = c(
"exact response value for profile 1" = 1,
"exact response value for profile 2" = 2
)The strings on the left are not new profile names created by
reshape_projoint(). They must match the ends of the values
stored in every outcome column, including capitalization and whitespace.
The numbers on the right refer to the profile positions encoded in
columns such as K-1-1-* and K-1-2-*. Although
shorter suffixes such as "A" and "B" are
supported, using the complete exported response strings is clearer and
more auditable.
outcomes <- paste0("choice", 1:8)
outcomes1 <- c(outcomes, "choice1_repeated_flipped")
out1 <- reshape_projoint(
.dataframe = exampleData1,
.outcomes = outcomes1,
.choice_map = c("Community A" = 1, "Community B" = 2),
.alphabet = "K",
.idvar = "ResponseId",
.repeated = TRUE,
.flipped = TRUE
)Key Arguments:
.outcomes: Outcome columns (include repeated task
last).choice_map: Verified mapping from exact exported
response values to Qualtrics profile positions 1 and 2.idvar: Respondent ID variable.alphabet: Variable prefix (“K”).repeated, .flipped: If repeated task
exists and is flippedNot-Flipped Repeated Task
outcomes <- paste0("choice", 1:8)
outcomes2 <- c(outcomes, "choice1_repeated_notflipped")
out2 <- reshape_projoint(
.dataframe = exampleData2,
.outcomes = outcomes2,
.repeated = TRUE,
.flipped = FALSE
)No Repeated Task
.fill Argument: Should You Use It?
Use .fill = TRUE to “fill” missing values based on IRR
agreement.
fill_FALSE <- reshape_projoint(
.dataframe = exampleData1,
.outcomes = outcomes1,
.fill = FALSE
)
fill_TRUE <- reshape_projoint(
.dataframe = exampleData1,
.outcomes = outcomes1,
.fill = TRUE
)Compare:
selected_vars <- c("id", "task", "profile", "selected", "selected_repeated", "agree")
fill_FALSE$data[selected_vars]## # A tibble: 6,400 Ă— 6
## id task profile selected selected_repeated agree
## <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 R_00zYHdY1te1Qlrz 1 1 1 1 1
## 2 R_00zYHdY1te1Qlrz 1 2 0 0 1
## 3 R_00zYHdY1te1Qlrz 2 1 1 NA NA
## 4 R_00zYHdY1te1Qlrz 2 2 0 NA NA
## 5 R_00zYHdY1te1Qlrz 3 1 1 NA NA
## 6 R_00zYHdY1te1Qlrz 3 2 0 NA NA
## 7 R_00zYHdY1te1Qlrz 4 1 0 NA NA
## 8 R_00zYHdY1te1Qlrz 4 2 1 NA NA
## 9 R_00zYHdY1te1Qlrz 5 1 1 NA NA
## 10 R_00zYHdY1te1Qlrz 5 2 0 NA NA
## # ℹ 6,390 more rows
## # A tibble: 6,400 Ă— 6
## id task profile selected selected_repeated agree
## <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 R_00zYHdY1te1Qlrz 1 1 1 1 1
## 2 R_00zYHdY1te1Qlrz 1 2 0 0 1
## 3 R_00zYHdY1te1Qlrz 2 1 1 NA 1
## 4 R_00zYHdY1te1Qlrz 2 2 0 NA 1
## 5 R_00zYHdY1te1Qlrz 3 1 1 NA 1
## 6 R_00zYHdY1te1Qlrz 3 2 0 NA 1
## 7 R_00zYHdY1te1Qlrz 4 1 0 NA 1
## 8 R_00zYHdY1te1Qlrz 4 2 1 NA 1
## 9 R_00zYHdY1te1Qlrz 5 1 1 NA 1
## 10 R_00zYHdY1te1Qlrz 5 2 0 NA 1
## # ℹ 6,390 more rows
Tip:
- Use .fill = TRUE for small-sample or subgroup analysis
(helps increase power).
- Use .fill = FALSE (default) when in doubt for safer
estimates.
If you already have a clean dataset, use
make_projoint_data():
out4 <- make_projoint_data(
.dataframe = exampleData1_labelled_tibble,
.attribute_vars = c(
"School Quality", "Violent Crime Rate (Vs National Rate)",
"Racial Composition", "Housing Cost",
"Presidential Vote (2020)", "Total Daily Driving Time for Commuting and Errands",
"Type of Place"
),
.id_var = "id",
.task_var = "task",
.profile_var = "profile",
.selected_var = "selected",
.selected_repeated_var = "selected_repeated",
.fill = TRUE
)Preview:
## <projoint_data>
## - data: 6400 rows, 13 columns
## - labels: 24 levels, 4 columns
To reorder or relabel attributes:
Edit the CSV (change order, label columns; leave
level_id untouched)
Save it as “labels_arranged.csv” or something else.
Reload labels:
Compare using our example:
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