Employment laws should be very clear about which types of personal information employers can bring into the workplace, and which types they can disclose. Employers shouldn't be able to use personality assessments, as these can be used to create a volatile work environment. An employer can tell through the interview process whether or not an individual is a good fit.
An employer's use of data from third parties should be very limited. For example, people's financial situations can be used against them. How much money do they have in the bank? What kind of credit do they have? Are they in a position where they can leave their job? Can they afford an attorney? Other examples include a person's marital or dating status. Some people can see these things as weaknesses.
Disclosures to third parties are another issue. An employee's whereabouts and schedule are strong examples. Workers have certain rights under laws with respect to invasion of privacy.