There is no official definition of 'collective dismissal'. The four acts referred to here define the terms of dismissal and other cooperation procedures in different types of organisations. The employer is obliged to negotiate with the employees whenever the employer considers measures which may lead to notice of terminations or lay-offs and affect one or several employees.

The employer must give notice before the start of the cooperation negotiations so as to allow the employee representatives to properly prepare for the negotiations. The negotiations are generally carried out between the employer and employee representatives, but also the concerned employee(s) may participate. The employer must provide the employee representatives with

• information regarding the grounds of the intended measures;
• initial estimates of numbers of employees affected;
• principles determining which employees will be affected; and
• a time estimate of the implementation of the measures.

The employer must also notify the public employment services (PES) of the intended measures, and in cooperation with the PES investigate available public services to support employment. At the end of the cooperation negotiations, the employer must present a report on its intended actions to the employee representatives.

There is no defined minimum for company size or minimum number of affected employees for a collective dismissal. However, in undertakings employing at least 20 employees, a cooperation procedure is necessary in order for a dismissal to be valid, while companies with fewer than 20 employees are not bound by this obligation. Procedures may differ somewhat with the type of organisation (company, state or local government), the size of the organisation and the number of affected employees. For instance, measures concerning 10 employees or more generally require a minimum negotiating period of six weeks, but in a company employing over 20 but fewer than 30 people, the minimum negotiating period is 14 days. In addition, procedural requirements regarding information provided by the employer to the worker's representatives also differ somewhat with the number of affected employees.