Legally, no assessment should count for more than 1/3 of the selection process and no assessment should be a go/no-go decision on its own.

A bigger mistake hiring managers make is administering assessments too late in the process. It is common for managers to assess candidates as the final step “just in case something pops up.” By the time a candidate gets to this stage of the process, hiring managers have emotionally committed to the candidate and cannot objectively interpret the results. If hiring managers are deep into the process and committed to a candidate, they shouldn’t bother assessing.
Assessing candidates after the first interview allows the hiring manager to confirm their observations and objectively focus on concerns in follow-up behavior-based interviews and behavior-based reference checks.
Empowered hiring managers assess their candidates at the right time in the process for successful results.