- Reducing project duration is reducing time of activities on critical path to shorten overall duration of the project. It’s considered on benefit of firm if project finished as we need, the reasons come from customer requirements, contract commitments, time to market pressures (more benefit if can operate in the right time such as department store can sell in cristmas or new year, electric plant can operate in summer), incentive contracts (bonuses for early completion because projective can save money and firm can operate outcome before competitors), unforeseen delays (avoil delay of project such as problem from rain for construction work, malfunction in equipment system), overhead & goodwill costs (save cost for overhead), pressure to move resources to other project.  

- Some text said that “time is money” it meaning that if project finished in time shorter, we can use outcome of project to make money or benefit as soonest. If project delayed, time to making money or benefit will late also. And also reducing or extent project duration will effect to cost of project, it decreasing or increasing will belong to the physical of each work. Some works may be take high cost if we finish them in time shorter and also effect to the quality of work. Then reducing project duration will consider optimizing between total cost (direct costs and indirect costs) and time, and considering for the quality as customer need. Direct cost will low if take long time but it is fixed when go to specify point where cost cannot less than. Indirect cost will increase linear proportion with time (long time/high cost, short time/low cost). Example, the job must be finished within 10 days by 10 workers, and process of work need 2 workers to do the job in the same time, can see direct cost and indirect cost as table below.


 cost curve


Reducing project duration, we will consider reducing time on activity that less of cost per day to shorten, and reducing time must be maintain crash duration of work. Crash duration of work is possible time to do the work (time limit). Cost increment is difference between worked cost in crash duration and worked cost in normal duration. Cost increment will used for calculate cost per day to shorten. And please be careful when reducing time of activity in critical path because another float path may be change to critical path.