It can add a common measure
WashU can read an SAT or ACT beside students from very different high schools. The score may clarify academic preparation when the local transcript is unfamiliar, but its meaning still depends on course access and performance.
It cannot replace curriculum
Architecture and Art portfolios, engineering preparation and Arts & Sciences breadth remain separate evidence streams from testing. Admissions readers can see whether the student pursued the strongest appropriate sequence; a composite does not manufacture missing preparation.
It can reveal a section imbalance
Highest individual scores are considered; ACT Science is optional and excluded from the core superscore calculation. A section-level plan is therefore more useful than repeatedly chasing a round total without diagnosing the limiting skill.
It cannot predict admission
The Class of 2029 middle 50% was 1490–1550 SAT and 33–35 ACT among students reporting scores. The cohort contains admitted students, not a mechanical rule. Students below, inside and above a range can receive different decisions because the application is broader.
It can guide timing
WashU accepts self-reported scores and verifies them after enrollment. The useful final sitting must leave enough time for the route WashU accepts and for the applicant to confirm that the checklist is complete.
It cannot freeze the policy
For WashU, fall 2027 policy confirmed describes the verified scope. Testing policies, optional sections and reporting instructions can change; the application term must remain attached to every operational decision.