CDI Knowledge Exam Details

***The CDI-Knowledge Exam will be retired by the end of 2020 and this information will be removed and/or archived from this website shortly after.

CDI Knowledge Exam

Once you meet the eligibility for taking the CDI Knowledge exam, you can apply and pay for your CDI-Knowledge exam by logging on to your RID Account (or creating an account if you do not already have one) and clicking on “Apply for CDI Certification” in the orange tile titled “Apply for Certification.” Follow the instructions and upload training documentation. Payment can be made with a MasterCard or VISA.

    • RID staff will review training documentation within 10 business days.
    • After approval of the 40 hour training you will see the button to “Register for the CDI Knowledge Exam” in the yellow tile on your account.
    • Complete and send a hard-copy application form with payment of appropriate fees to CASLI

It is recommended that you apply at least five weeks in advance of when you would like to take the exam to allow plenty of time for the application and registration process. It is your responsibility to ensure that CASLI and RID receive all required documentation. Processing may be delayed if you submit an application that is incomplete.

The CDI Knowledge Exam is a paper and pencil exam administered by CASLI test sites. CASLI test sites are located around the country. Each test site has a Test Administrator who is responsible for the logistics of the testing room facilities and equipment.

You can view the current map of Test Sites here.

All candidates must have their Authorization To Test (ATT) Letter in order to schedule an appointment. 

Once you have paid for your exam and receive your Authorization to Test (ATT) Letter, your next step is to contact the CASLI test site of your choice to schedule your exam appointment. When you contact the test site, the test administrator will confirm your appointment date and time and provide you with information on reaching the testing location.

Test sites may be closed or may experience delays during severe weather, natural disasters, or other emergencies. Exam appointments that the test site cancels under such circumstances may be rescheduled at no additional cost. Contact the test administrator at the test site for rescheduling information.

If it is more than two business days from your scheduled exam date you can reschedule or cancel your exam. If you are eligible to cancel/reschedule your exam, you will need to contact your test site immediately and include CASLI. There is no rescheduling fee at this time.

If it is less than two business days from your scheduled exam date you cannot reschedule or cancel your exam. If you do not reschedule at least two business days prior to your exam appointment and/or you do not show up for the exam, it will be considered a missed appointment and you forfeit your exam and all related exam fees. You would then be required to register and pay for the exam again in order to sit for it in the future. Please note that the only exception to this rescheduling policy is a documented, excusable emergency situation.

If you miss your scheduled exam appointment due to an excusable emergency situation, you must contact CASLI within three business days following the documented emergency (or the first available opportunity if the nature of the emergency prevents you from contacting us) to be considered for an approved, free, rescheduled exam.

Excusable emergency situations include:

  • The death of an immediate family member
  • Accident, illness, or hospitalization of you or an immediate family member (verified by a doctor)
  • A natural disaster

Documentation of the emergency must be submitted to CASLI. If CASLI verifies that the emergency qualifies, your application and exam fees may be applied to another exam appointment. After approval of a free rescheduled exam, you can contact the test site of your choice and schedule your exam.

If the candidate cancels the scheduled exam appointment after the deadline or misses the scheduled exam appointment for any reason other than an excusable emergency situation that is approved by CASLI, it will be considered a missed appointment, which forfeits the exam and all related fees. The candidate would then be required to register and pay for the exam again in order to sit for it in the future.

If you have paid for but have not yet scheduled an appointment for the CDI Knowledge Exam and decide you no longer wish to take the exam, CASLI will either refund your payment or credit the exam fee to your account, minus the $15 non-refundable application processing fee, within two years of the paid date. After two years, the exam fee cannot be refunded but can be credited to your account (minus the $15 non-refundable application processing fee). Please submit your request in writing to CASLI. Refunds will be processed in the same manner the original payment was made (e.g.. if you originally paid by check then you will be refunded by check).

The CDI Knowledge Exam tests for knowledge appropriate to an interpreter holding national certification and covering, professional roles and responsibilities, preparation for service delivery, provision of service, and post-service closure. Additionally, see the list of suggested reference materials (see – CDI Knowledge Examination Suggested Reference Materials).

The following is a detailed outline of the four domains of the examination with an indication in parentheses of the approximate percentage of questions devoted to each area. 

Four Domains of the Examination

CDI Knowledge Exam Format

The CDI Knowledge Exam is administered in both English, using a paper exam booklet, and ASL, using two DVDs. All answers must be recorded on a Scantron sheet. This exam consists of 100 multiple-choice questions that assess whether a candidate has the knowledge required to achieve national certification. Candidates have up to three (3) hours to complete the exam.

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On the Day of Your CDI Knowledge Exam

You should wear professional attire and dress in layers in case the exam room is too hot or too cold.

Your test administrator will provide you with the location of your test site. Plan your travel carefully so that you arrive at the test site at least 10 minutes before your scheduled appointment time.  If you arrive at the test site late, you may be denied access to the test site, and it will be considered a missed appointment.

You must bring a hard copy of your entire Authorization to Test Letter. You can access your ATT Letter by logging into your account and clicking on “Download ATT Letter” in the yellow tile titled “Certification Application Status.” Your ATT Letter is your proof of eligibility to take the exam.

CASLI employs very strict testing security measures.  One level of security involves your identification. You must bring at least one form of identification that meets the following requirements:

Your identification (ID) must:

  • Display your name exactly as it appears on your Authorization to Test Letter
  • Have a permanently-affixed photograph of your face
  • Be current — expired IDs will not be accepted
  • Be an original document — no photocopies will be accepted

Acceptable forms of identification are:

  • Government-issued driver’s license
  • State ID card
  • Passport
  • Military ID (except those with chips)
  • Permanent resident visa or green card

Unacceptable forms of identification include:

  • Employee identification or work badge
  • University/college identification

If you do not present acceptable identification, you will not be allowed to take your exam and it will be considered a missed appointment, even though you appeared at the test site.

The test administrator at each test site has been trained in the procedures specific to CASLI exams.  The test administrator will guide you through the steps that have been developed by CASLI.  The following is what you can expect when you arrive at the test site:

a. You may not bring any personal items with you to the test site, other than your personal identification and your ATT Letter. (This includes purses, wallets, watches, jewelry, cell phones, calculators, etc.) If you do bring personal items to the test site, the test administrator will show you where to store them. Neither test administrators nor CASLI will be responsible for lost or stolen items.

b. You must provide one form of acceptable identification. The test administrator will verify that the name on your government-issued identification card matches the name on the ATT Letter, that the photo is of you, and that your RID number is correctly displayed on the Candidate/Vignette Indicator Card.  You must keep this identification with you at all times during the exam.

c. You will be provided with all the exam materials: ASL DVDs, exam booklet, scantron answer sheet, pencil, and scratch paper, if needed. Candidates can not mark or damage the exam booklet. If the booklet is returned marked or damaged, you  will be assessed a fee which must be paid to CASLI.

d. You will not be allowed to bring any food or drink into the testing room.

e. You will be escorted into the testing room by the test administrator. The test administrator will show you where to sit.

f. You must complete the CASLI Candidate Agreement form, indicating agreement to abide by the policies and procedures of the RID testing process and to maintain confidentiality in regard to RID exam materials. If you do not sign this form, you will not be allowed to take the exam, and it will be considered a missed appointment, even though you appeared at the test site.

You must remain seated for the duration of the exam. You can choose to follow the questions and answers from the exam booklet and or the ASL DVD. You are allowed to skip between questions. You can request and use scratch paper during the exam. All scratch paper will be collected at the end of your exam. You should be provided the CDI Knowledge Exam Candidate Feedback Form. If you were not provided this form or would like to submit additional information please email

CDI Knowledge Exam Scoring

The test consists of 100 multiple-choice questions. All questions are of equal weight, and you will receive one point for each correct answer. Incorrect and unanswered questions receive no points. You are encouraged to answer all questions since there is no penalty for incorrect answers. You must receive a score of 72 or better to pass the exam.

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CDI Knowledge Exam Score Reporting

CASLI will endeavor to score the CDI Knowledge Examination and to report scores to candidates within 30 days. Following the examination scoring, CASLI will send you an email to the email address listed in your account. Please keep your contact information in your account up-to-date to prevent notification delays.

All candidates, regardless of their results, will receive their exact score and the score analysis (the score received on each domain of the exam answered correctly).

You can access your exam results by logging into your account and clicking on the purple tile titled, “View Your Exam History.”  Next to the exam you would like to see your results for, please click on “Download Score Report.”  This PDF document will automatically download to your computer.

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CDI Knowledge Exam Retakes

If you fail the CDI Knowledge Exam, you may apply and pay for a CDI Knowledge Exam retake after a six-month waiting period.  The six-month waiting period begins from the date you originally took the Exam; this is regardless of when you received your exam results. The portal is designed so you cannot purchase a retake until your six months has passed. Then the link to purchase the retake will appear. There is a reduced price for exam retakes. If it has been longer than five years since the date on the results letter of your most recent passing of the CDI Knowledge Exam, you must start the certification process over and pay the first time CDI Knowledge Exam fee.

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