Legacy advantage in RD or just in ED?

If an applicant’s parent graduated from Williams, is there any slight legacy advantage? (Note: middle class family, not a major donor. Assume applicant’s scores and grades are typical of Williams admits and he would be a strong applicant even without any legacy status.). If so, is the (slight) advantage more pronounced in the Early Decision round or can it also help in the Regular Decision round?

I’m not sure if they still do this but in the past admissions would offer an evaluation of a legacy student’s chances of admission. I would contact them and see where you stand. Common sense says ED gives some advantage over RD, though the stats are a bit misleading.

Will help in either. Clearly not the deciding factor. It is considered “important” (in a considered-important-very important spectrum) according to their information this year posted on CB.

https://bigfuture.collegeboard.org/college-university-search/williams-college

Some years ago my younger son was told in a legacy interview at admissions on campus that he would still have his legacy edge RD and didnt need to apply ED. His stats were strong. If they still offer the legacy interviews I strongly recommend scheduling one.