Please see this excerpt from the WJ IV COG Examiner's Manual. 
Please review full details starting on page 10 of the WJ IV COG Examiner's Manual.

Because professional titles, roles, and responsibilities vary across jurisdictions (even within school districts themselves) it is impossible to equate competency to professional titles. 

As such, the Standards for Educational and Psychological Testing suggest that it is the responsibility of each school district to determine who, under its aegis, is qualified to administer and interpret the WJ IV COG. Although we can provide recommended qualifications based on standards, the school district and/or overseeing organization has the final say in who can and cannot administer our assessments.

It is recommended that your special education and/or organizational leadership review the qualification information noted in the WJ IV COG examiner's manual to then determine who under their supervision can administer and interpret the WJ IV COG.

"Any person administering the WJ IV COG needs a thorough knowledge of the exact administration and scoring procedures and an understanding of the importance of adhering to standardized procedures. To become proficient in administering the WJ IV COG, examiners need to study the administration and scoring procedures carefully and follow the procedure precisely...

Competent interpretation of the WJ IV COG requires a higher degree of knowledge and experience than is required for administering and scoring the tests. Graduate-level training in cognitive ability assessment and a background in diagnostic decision-making are requisite. Only trained and knowledgeable professionals who are sensitive to the conditions that may compromise, or invalidate, standardized test results should make interpretations and decisions. The level of formal education needed to interpret the WJ IV COG is typically documented by the successful completion of an applicable graduate-level program that includes, at a minimum, a practicum-type course covering administration and interpretation of standardized tests of cognitive abilities. Furthermore, many qualified examiners possess state, provincial, or professional certification/licensure in a field that includes as part of its formal training and code of ethics the responsibility for rendering cog ability, learning disability, or informational processing assessment and interpretation services."

Our special needs assessment qualifications guide can also be found here: Qualifications Guide