Even if you outsource HR duties, you can be liable for vendors' mistakes.

Employers may assume that outsourcing an HR function to an expert provider will insulate them from liability in case of a legal mistake. That's not always true.

It's vital to read the fine print in vendor agreements (before you sign) and perform quality control to ensure vendors follow the law.

Recent case: The ADA only allows employers to conduct post-offer medical screenings for reasons that are consistent with business necessity. The ADA also makes it unlawful to discriminate against disabled applicants.

JBS Carriers, a trucking company, typically offered jobs to applicants contingent on passing a medical exam. JBS outsourced pre-hire exams to ErgoMedical, who gave negative recommendations to any applicant who failed the screening, questionnaire or physical test.

Cindy had 30 years of truck driving experience when JBS offered her a job. She had a sore shoulder at her exam, something she attributed to carrying...