When it comes to supervising employees or the like in the performance of professional services on a project, it is imperative to consider what obligations you have in supervising that employee’s work.
As you would imagine, when supervising another person, you must yourself be competent in the task being asked of that person. Supervision, in its very definition, is the process of watching and directing what someone does and/or how it is done. If you cannot competently perform the task yourself, then it would seem a given that you cannot properly supervise the carrying out of that task, and as such, should refrain from doing so.
For example, do you think one should be supervising (and be responsible for) say a structural engineer when their background and experience is in civil engineering?
In 2015, the Queensland Civil and Administrative Tribunal considered this exact question with respect to legislation whereby a registered professional engineer is only to provide services in their relevant fields of registration (that is civil, mechanical, structural etc). In this case, a registered professional engineer was supervising the performance of structural engineering services by an unregistered employee. Neither had appropriate experience in the field of structural engineering. The supervising engineer then relied on the drawings prepared by the employee. On investigation, the Board of Professional Engineers Queensland found that the designs (the subject of the supervision) were inadequate and contained a number of defects containing incorrect calculations and which did not comply with either the relevant Australian Standard or the Building Code of Australia.
Member Gordon, in Board of Professional Engineers of Queensland v Moodie  QCAT 44 at  stated that:
“It is of significance that Mr Moodie’s career and experience has been primarily focussed on civil engineering projects rather than on work as a structural engineer where his experience is limited.”
Although Mr Moodie accepted that he shouldn’t have offered structural engineering services, Member Gordon stated that Mr Moodie ought not have been in a position of supervising the work of an employee of the company who was unregistered with respect to structural engineering work, nor certifying the designs because of his own lack of experience and efficiency in considering or revising them.
The engineer was fined and ordered to pay the Board’s legal costs.
Long story short, make sure you know what you are doing yourself before you think of supervising (and relying on) employees work.