LC classification

This chart shows the Library of Congress class — the first letter of the call number — for each institution's records. The call number is taken from the first place it appears among several: the standard 050/090, or a local holdings/item field, which varies by institution (852, 950, 900, …).

We err toward not claiming an LC classification: the 852 holdings field is only trusted when its scheme indicator says LC (many hold Dewey, NLM, or local schemes instead), Dewey and NLM numbers are skipped, and only the 21 letters LC actually uses are counted. Electronic resources typically carry no call number at all. So the shares below are within each institution's confirmed LC-classified records, and each column sums to ~100%.

See the completeness chart for how many records have a confirmed LC classification — a figure that is deliberately conservative.