The phrase "skill deficits" refers to a lack or shortage of abilities or talents in a particular area. It means that someone is missing or weak in certain skills needed for a task or activity. Full definition
Social skill deficits in children with attention - deficit hyperactivity disorder. (psiholoska-obzorja.si)
Significant improvements in social - emotional competence and behavior were made by children who started the school year with skill deficits in these areas. (cfchildren.org)