Determines which structural period a given year belongs to based on known changes in RSF's data format and calculation methodology.
Value
Character. One of: "period_1" (2002-2012), "period_2"
(2013-2021), or "period_3" (2022-2026). Returns NA for
year 2011 (no official RSF data).
Details
This function determines the structural period a year belongs to, which drives column mapping and normalization logic.
**Important:** Encoding is NOT period-based. Use detect_csv_encoding()
to determine per-file encoding. Period 1-2 (2002-2021) are UTF-8 despite
the structural naming; Period 3 (2022-2026) mixed UTF-8 (2022-2024) and
ISO-8859-1 (2025-2026) without warning.
**Period 1 (2002-2012):** - 16 columns with fixed structure - Delimiter: semicolon (;) - Scores not comparable across years (within-year ranks only)
**Period 2 (2013-2021):** - 16 columns, same structure as Period 1 - Delimiter: semicolon (;) - Scores comparable across years (new calculation method introduced)
**Period 3 (2022-2026):** - 22-25 columns (varies by year) - Delimiter: semicolon (;) - Major restructuring: columns reordered, score dimensions added - Column names vary by year (e.g., "Score" vs "Score 2026")