Definition. Matched cells and held-fixed coordinates [ftip-009U]
Definition. Matched cells and held-fixed coordinates [ftip-009U]
Let \(J\) index the coordinates of an experiment cell \(\mathfrak c\) from Definition [ftip-009T]. For \(S\subseteq J\), two cells \(\mathfrak c\) and \(\mathfrak c'\) are matched outside \(S\) when
\[ \mathfrak c_j=\mathfrak c'_j\qquad \text {for every }j\in J\setminus S. \]The coordinates in \(J\setminus S\) are the held-fixed coordinates; those in \(S\) are the declared intervention coordinates. Equality means equality at the resolution recorded by the experiment, including evaluation sample size when that size affects the reported statistic.
A matched comparison licenses a contrast between the recorded cells. It does not show that a named coordinate is internally atomic. In particular, matching outside the starting-policy coordinate leaves the composite-checkpoint qualification of Remark [ftip-009S] in force.