CREATE TABLE table_23269 ("Institution" TEXT, "Location" TEXT, "Nickname" TEXT, "Founded" FLOAT, "Type" TEXT, "Enrollment" FLOAT, "Joined" FLOAT)

When has Clark University joined the Conference?
SELECT MAX("Joined") FROM table_23269 WHERE "Institution" = 'Clark University'
SELECT MAX("Joined") FROM "table_23269" WHERE "Institution" = 'Clark University'