Close the boundary: categorical encoding rewrites tokens, not model claims.

highlighted = computed this step

What categorical encoding does

It rewrites category tokens into explicit integer columns for a later method to read.

tokens{0,1} columns\text{tokens}\rightarrow\{0,1\}\text{ columns}
Categorical Features ExactlyExact one-hot columns from a pinned category list.one-hot columns from pinned category orderrowcolorredbluegreenotherAred1000Bblue0100Cgreen0010category order: red, blue, green; other reservedpreprocessing rewrites category tokens into indicator columnsunknown category uses the pinned other-column policyNOT training; NOT learning; NOT generalizationNOT accuracy; NOT calibration; NOT a guarantee of model qualityNOT probability truth

What it does not do

It does not train a model and does not prove accuracy, calibration, model quality, or probability truth.

preprocessing only\text{preprocessing only}
Unknown Category PolicyExact other-column policy for a new category token.unknown category uses other columnrowcolorredbluegreenotherAred1000Bblue0100Cgreen0010Dyellow0001unknown category to other columnpreprocessing rewrites category tokens into indicator columnsunknown category uses the pinned other-column policyNOT training; NOT learning; NOT generalizationNOT accuracy; NOT calibration; NOT a guarantee of model qualityNOT probability truth

The honest boundary

This book pins one category list, one one-hot table, and one unknown-category policy. It is NOT training, NOT learning, NOT generalization, NOT accuracy, NOT calibration, NOT a guarantee of model quality, and NOT probability truth.

category tokens become explicit indicator columns\text{category tokens become explicit indicator columns}
Unknown Category PolicyExact other-column policy for a new category token.unknown category uses other columnrowcolorredbluegreenotherAred1000Bblue0100Cgreen0010Dyellow0001unknown category to other columnpreprocessing rewrites category tokens into indicator columnsunknown category uses the pinned other-column policyNOT training; NOT learning; NOT generalizationNOT accuracy; NOT calibration; NOT a guarantee of model qualityNOT probability truth