Generate materials for each condition — generate

Ask a model to write experimental materials from your design. Each row produces n_versions separate responses, following Porter and Velez (2022). You can use this for vignettes, quotations, or other short texts.

Usage

generate_materials(
  design,
  template,
  chat,
  n_versions = 3L,
  seed = NULL,
  max_active = 10,
  rpm = 500
)

Arguments

design: A data frame of conditions, typically from design_conditions. Column names become {placeholder}s in template.
template: A glue-style string used to build the per-condition instruction. Column names from design are available as {name}.
chat: An ellmer Chat object used for every condition. Its system prompt should carry only task-general instructions (length, register, format), never condition-specific content. Use a fresh chat with no conversation history; previously used chats are rejected.
n_versions: Number of independent realisations per condition (default: 3).
seed: Optional integer seed recorded in the provenance attributes. Note that most providers are not bit-reproducible even at temperature 0.
max_active: Maximum concurrent requests.
rpm: Requests per minute limit.

Value

A tibble of class llm_materials: all columns of design, plus material_id, version, prompt, and text. Failed generations keep their row with text = NA. Generation provenance is stored in the "provenance" attribute.

Keep the system prompt general

The same system prompt applies to every condition. I put instructions about length and format there, and condition-specific wording in the template. generate_materials() warns if the system prompt names a factor level. Use a fresh chat so earlier conversation turns don't enter the requests.

References

Porter, E., & Velez, Y. R. (2022). Placebo selection in survey experiments: An agnostic approach. Political Analysis, 30(4), 481-494.

Examples

if (FALSE) { # \dontrun{
design <- design_conditions(
  frame  = c("economic", "moral"),
  source = c("expert", "layperson")
)

chat <- ellmer::chat_openai(
  "You write short, neutral survey vignettes. Return only the vignette.",
  echo = "none"
)

materials <- generate_materials(
  design,
  template = "Write a 60-word quote about a carbon tax from a {source}
              emphasising the {frame} perspective.",
  chat = chat,
  n_versions = 3
)
} # }