Where does interpolation collide?

In textual criticism, an interpolation is material that was not in the original text but was inserted later by a scribe or editor (a marginal gloss that crept into the body, a spurious line, an 'improving' addition), which the critic must detect and bracket or remove to recover what the author actually wrote. West's Textual criticism and editorial technique treats how such intrusions are spotted and handled in Greek and Latin texts. The referent is an alien insertion in a transmitted text, unrelated to estimating a value between measured data points.[1]

Unit

The inserted words or lines that are not authorial

Recovery means

Not applicable

Measured by

Judged by internal evidence (style, metre, logic) and by manuscript witnesses that lack the passage

In numerical analysis, interpolation is the construction of a function (typically a polynomial or spline) that passes exactly through a set of known data points so that values at intermediate inputs can be estimated. The classical Newton and Lagrange formulas and modern spline methods are set out in texts such as Burden and Faires's Numerical analysis. The referent is a method for filling gaps between sampled values, measured by how closely the interpolant tracks the underlying function; it has nothing to do with a corrupt line slipped into a manuscript.[2]

Unit

The estimated value at an input between the sampled points

Recovery means

Not applicable

Measured by

Assessed by the interpolation error between the fitted function and the true values at unsampled points