The phrase "poor supervision" refers to a situation where someone in charge or responsible for overseeing something fails to do so effectively. Full definition
The duo's escape was aided by lax security at an employee checkpoint, poor supervision of correction officers and a botched internal investigation into Mitchell's personal relationship with one of the inmates, according to interviews with law enforcement sources and state correction officials. (nystateofpolitics.com)
If the Dr's recommendations are followed, it is rare to develop any problems and those that do develop can usually be traced to poor supervision by the owner. (arkansasveterinarysurgerycenter.com)
Similarly, poor supervision also exerted indirect effects on inattention via child conscientiousness as well as significant indirect effects on hyperactivity - impulsivity via its impact on both child reactive control and conscientiousness. (link.springer.com)