What the evidence turns on
Disputes about selection and assessment rarely turn on whether a test was administered correctly. They turn on whether the instrument was valid for the decision it was used to justify, and whether it functioned equivalently across the groups it was applied to. Those are measurement questions with established technical answers, and they are answerable from the instrument, its documentation and its data.
The work covers test validity and job relatedness, adverse impact and differential item functioning, measurement invariance across language and group, and algorithmic fairness where the screening is done by a model rather than a questionnaire. The last of these is where a growing share of instructions arrive, because vendors increasingly claim fairness properties that their own validation evidence does not support.
How instructions are taken
Written opinions, rebuttal of another expert, and testimony. Instructions come from employment and discrimination proceedings, regulatory matters, arbitration, and pre action assessment where a party wants to know how strong its position actually is before committing to it.
Every instruction begins with a conflict check against a standing register. Instructions are taken in three forms: an independent validation opinion on whether an instrument supports the use made of it, a rebuttal of another expert’s report, and instructed testimony including deposition and cross-examination. A validation opinion typically takes two to four weeks from receipt of the instrument and its documentation. Fees are hourly for review and daily for hearing attendance, with fixed fees available for validation opinions, and are sent on request before any work begins. They do not depend on the outcome.
What this is not
It is not a clinical or psychological assessment of any individual, and it does not extend to opinions on the state of mind of any person. The subject is the instrument, and the inference somebody drew from it.