In inbound, calls are considered lost calls if the caller hangs up before a customer service agent can answer the call. The number of these unanswered calls (lost calls) increases when there are too few staff available (shortage), which can happen, for example, during unexpected call peaks. In the case of active customer contact, lost calls are connections that are set up via a predictive dialler and accepted by the called party, but are terminated again before a conversation is established due to the lack of a free employee. In order to keep the number of lost calls generally low, intelligent staff planning is important. This makes it possible to always have the right number of employees on site.