The problem is to schedule a number of jobs over a group of resources. In this context, a job is a set of activities that must be carried out, one after another. Each resource can process only one single activity at a time.

For each job, there is a due date, that is, the ideal date to finish this job by finishing the last activity of this job. If the job is finished earlier than the due date, there will be a cost proportional to the earliness. Symmetrically, if the job is finished later than the due date, there will be a cost proportional to the tardiness.

As "just in time" inventory management becomes more and more important, problems like this occur more frequently in industrial settings.