DMS includes the option to schedule by critical ratio.  The critical ratio is calculated by:

Time remaining in hours until job due date / Work remaining in hours for the job

When you select to schedule by critical ratio, the scheduler calculates and saves the critical ratio for all jobs to be scheduled.  The calculation takes place during a schedule run after the resource capacities have been created and before any scheduling of jobs takes place.  An index is used to determine how much a task is on schedule. A value of 1.0 indicates there is enough calendar time to complete the job.  A value less than 1.0 indicates that there is not enough calendar time to complete the job.  A value larger than 1.0 indicates there is more than enough calendar time to complete the job.

Note that just because a critical ratio value is 1 or greater than 1 does not mean that the job is one time.  Capacity constraints may cause a job to be late even though enough calendar time to complete the job exists. 

Also see Scheduling