Reading, Grammar and Arithmetic on the CDCR Test
The largest share of CDCR's sample is reading a document accurately, spotting a grammar or spelling error, and adding or subtracting. None of it is hard; most of what people lose is to speed and to assumption.
Reading a document you have been given
Schedules, completed forms and short passages of procedure. The answer is always in the document, and the wrong options are almost always real values from elsewhere in the same document — a duration from the wrong row, a number from the wrong column. That is what makes these questions fail: not difficulty, but reading across the line above the one you wanted.
Find the row or field the question names before you read anything across it. On a form, read down the labels first so you know what is recorded and what is not.
Grammar and spelling
CDCR's bulletin names "correct grammar and spelling" as knowledge the examination measures, and its sample shows the format: a short sentence with four words identified, one of which carries an error.
The errors worth rehearsing are the ordinary ones — subject-verb agreement across an intervening phrase ("a record of the inspections IS kept"), its and it's, their and there, fewer and less, and the spellings people get wrong at work: received, separate, occurred, maintenance, necessary, privilege, definitely.
The arithmetic, which is smaller than people fear
CDCR's sample states its own scope in the instruction: questions "that require the use of addition and/or subtraction". The bulletin says "basic arithmetic". There is no algebra, no percentage work and no geometry in what CDCR publishes, and you are not allowed a calculator.
What that means in practice is that the arithmetic is about accuracy under time rather than about method. The mistakes that cost marks are the carry dropped, the operands reversed, and one term left out of a running total.
Choosing the clearest description
One type gives you a completed form and four descriptions of it. The right answer reports every recorded field and adds nothing. A description that leaves out a field is wrong for being incomplete; a description that supplies a reason, an intention or a detail the form does not record is wrong for being unsupported, however plausible it sounds.
Sources
- CDCR — Sample Written Selection Exam for Correctional Officer · checked 2026-08-23
- CDCR — Correctional Officer (WY50-9662) Open Statewide Examination Bulletin, released 09/03/2024 · checked 2026-08-23