A latent variable is an unobserved attribute that influences observed outcomes, whose value must be inferred from its effects on observable variables rather than measured directly. This sixth and final article in the inaugural Foundations section of The Valuation Engineer Journal completes the conceptual pipeline of the issue: starting from a heterogeneous good, building a characteristics space, defining the hedonic price function, recovering implicit prices, fitting a regression, and arriving at the residuals as carriers of a structured signal about unobserved bundle components. The +$46,455 unexplained residual on Comp H from the previous entry is shown to reflect a latent kitchen-remodel attribute. The entry concludes by citing the Residual Component Analysis (RCA) methodology (Craytor, 2025) as the research program that treats this residual structure as a recoverable signal rather than discardable noise.