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Snowball Searches

Source: vignettes/Snowball.qmd

1 Overview

openalexSnowball provides snowball search utilities that build on the openalexPro pipeline. A snowball search starts from a set of key papers and follows citation links to collect cited and citing works. Results are stored on disk as parquet datasets and can be loaded back into R using read_snowball().

2 Basic workflow

2.1 1. Define keypapers

Keypapers can be identified by OpenAlex IDs or DOIs.

snowball_dir <- "./snowball_ids"
pro_snowball(
  identifier = c("W2741809807", "W2755950973"),
  output = snowball_dir,
  verbose = TRUE
)
snowball_dir_dois <- "./snowball_dois"
pro_snowball(
  doi = c("10.1016/j.joi.2017.08.007", "10.7717/peerj.4375"),
  output = snowball_dir_dois,
  verbose = TRUE
)

3 Reading results

Use read_snowball() to load nodes and edges. The output can be an Arrow Dataset (default) or collected into memory as tibbles.

snowball <- read_snowball(
  snowball = snowball_dir,
  edge_type = c("core", "extended"),
  return_data = TRUE,
  shorten_ids = TRUE
)

snowball$nodes
snowball$edges

4 Output layout

A snowball search writes a folder structure similar to the following:

snowball/
├── cited_json/
├── cited_jsonl/
├── citing_json/
├── citing_jsonl/
├── edges/
├── keypaper_json/
├── keypaper_jsonl/
├── keypaper_parquet/
└── nodes/

5 Tips

  • Use return_data = FALSE to keep large datasets on disk.
  • Use edge_type = "core" when you only need edges involving keypapers.