Download and parse IPEDS datasets programmatically

Verified steps

1. Browse the IPEDS Data Center at https://nces.ed.gov/ipeds/datacenter/DataFiles.aspx to identify the survey and year you need; IPEDS does not provide a REST API — data is distributed as annual ZIP archives of CSV files.
2. Construct the download URL for the desired survey file from the Data Center listing, then fetch the ZIP archive programmatically using an HTTP GET request; no authentication is required for public IPEDS data files.
3. Unzip the archive to extract the data CSV (e.g., hd2024.csv for the institutional characteristics survey for 2024) and its accompanying data dictionary CSV (e.g., hd2024_dict.csv), which maps column codes to human-readable variable names and value labels.
4. Parse the data CSV using the UNITID column as the primary key (the IPEDS unit identifier) to join across surveys; UNITID is stable across years for most institutions, though institutions can change UNITID when they close, merge, or split.
5. For multi-year trend analysis, loop over the target year range, download each survey-year archive, extract and parse the CSVs, and union them into a single data frame keyed by UNITID and year; reconcile variable name changes between years using the data dictionaries.
6. Filter out closed institutions by checking the CYACTIVE or CLOSEDAT fields in the institutional characteristics (HD) survey before joining with other surveys to avoid inflating counts with defunct institutions.