The Scheme language is standardized in the official IEEE standard and a "de facto" standard called the "Revised Report on the Algorithmic Language Scheme" (R"n"RS). The most widely implemented standard is R5RS (1998). The most recent standard, R7RS, provides "small" and "large" versions of the Scheme language; the "small" language standard was ratified in 2013. Scheme has a diverse user base due to its compactness and elegance, but its minimalist philosophy has also caused wide divergence between practical implementations, so much that the Scheme Steering Committee calls it "the world's most unportable programming language" and "a "family" of dialects" rather than a single language.