C.37.CF:4.2 - Choose the smallest informative contrasts
When only content changed in a fixed form, compare those two versions. When only form changed and the relevant content is preserved, compare those two forms.
When both changed and the receiving decision needs their separate contributions, use:
| Variant | Content | Form | What its comparison can address |
|---|---|---|---|
| A | Prior | Prior | The earlier usable answer and its limits. |
| B | Added or revised | Prior | B against A: the content difference in the prior form. |
| C | Same revised content as B | Proposed | C against B: the form difference at the revised content. |
| D, conditional | Prior | Proposed | Complete the crossed comparison if content/form interaction or transfer of the form effect across contents matters. |
The three-variant arrangement gives two local contrasts. It does not identify an interaction. Four cells make that question inspectable but supply neither replication nor causal identification by themselves.
If a cell cannot be constructed without changing another load-bearing feature, say so. A bundle comparison may still support a local choice. Do not describe it as an isolated content or form result.