The circa 1963 Louisiana literacy test is typical of the tests used throughout the South before passage of the Voting Rights Act to deny Blacks — and other non-whites — the right to vote. While state law mandated that the test be given to everyone who could not verify that they had at least a 5th-grade education, in real life almost all Blacks were forced to to take it even if they had a college degree while whites were often excused from taking it no matter how little education they had.
Determination of who "passed" and who "failed" was entirely up to the whim of the Registrar of Voters — all of whom were white. In actuality, whites almost always "passed" no matter how poorly they performed, and Blacks almost always "failed" in the selective judgement of the Registrar. On this 1963 test, for example, the Registrar was free to choose which portion of the Constitution to dictate — simple or complex — and was then the sole judge of the applicants written response (and where required their oral interpretation). The "citizenship test" component then asked questions about government and law, many of them obscure, and few people — Black or white — could correctly answer them all without advance study. If you were Black and missed one question you "failed," if you were white and couldn't even read the questions, you "passed."