Establishing order
An undisturbed deposit over another generally supports a later formation date. Linked relationships can establish occupation, abandonment and rebuilding sequences even when exact years remain unknown.
Order alone does not establish duration. Earlier and later events may be days or centuries apart; equal spacing in a sequence diagram does not imply equal elapsed time.
Comparisons require context
Artifact forms and decoration change through time. Assemblage comparisons and established production or use ranges provide context, beyond finding one superficially similar object.
An object can remain in use before deposition. For example, a coin genuinely deposited after its minting in 1782 constrains that deposit to 1782 or later; it does not prove deposition in exactly that year.
Combining sequences and dates
Tree rings, radiocarbon measurements and historical records can anchor parts of a sequence, subject to sample selection and association. One sample date does not automatically date everything found beside it.
Chronological models should distinguish observed relationships from interpretations and retain links between samples and target activities. Disagreement requires examining disturbance, residuality and assumptions rather than selecting only expected results.