This research monograph reports the literature of a research which evaluates the effectiveness of construction project schedules based on the Microsoft project planner. The success of construction projects largely depends on the quality of their schedules, which can be used to identify and proactively mitigate possible potential problems. The purpose of scheduling is to provide a road map for project accomplishment from inception to completion. Construction scheduling is commonly done using pieces of scheduling software such as the Primavera Project planner (P3), Microsoft Project Planner, and Sure track etc. These pieces of scheduling software always include inbuilt guide or help facility which assists the user to effectively use them to achieve optimum result. Though the project guide gives instructions and displays useful specific information in relation to the selected option, the MS Project guide as it is at the moment lacks ability to indicate scenarios where selected options are best suited or ability to indicate 'what-if' implications of selected options so that users can make informed choice of available alternatives particularly regarding constraint decision options. Different types of decisions are usually made during the construction scheduling process. It is noted that options taken in these decisions have different effects on the schedule performance. Also that before now in using the MS Project software, it is believed that the best practice is to enter duration estimates for tasks and allows MS Project to schedule the task start and finish dates. In this case the scheduling engine has no discretion of options other than the default start and finish dates. The focus of this research is on the effects of ALAP/ASAP decision constraint options taken during schedule development. As-late-as-possible date is a restriction that consumes positive float, mainly the free float to delay an activity as long as possible without delaying its successor. While As-soon-as-possible fixes a date for the activity to occur without consuming any float. That is, zero float consumption. Though this research scope covers Microsoft Project Planner, it is observed that Primavera Project Planner (P3) scheduling software has similar constraint features with those in Microsoft Project Planner. P3 provides the following eight constraint options: As Soon As Possible (ASAP); As Late As Possible (ALAP); Start No Earlier Than (SNET); Start No Later Than (SNLT); Finish No Earlier Than (FNET); Finish No Later Than (FNLT); Must Start On (MSO); Must Finish On (MFO) This literature module of this research has progressively demonstrated that the current practice of scheduling every floated activity to occur as soon as possible certainly does not produce optimum schedules. The study concludes that both experienced and young scheduling engineers lack the ability to go beyond the default option with reason. More importantly if different choice would have different effects on the project schedule, then the appropriate choice in the scenario should be sought. Since the mandatory constraints are applied in certain defined project scenarios, the question is, when should the flexible ALAP/ASAP constraints be applied or put more succinctly what is the relative advantage of ALAP over ASAP constraint scheduling options and in which project scenarios should it be used? Though it is recognised that the concept of float is an artificial construct of the CPM algorithm, when it is well understood and managed with the understanding of project specific attributes, resource specific attributes and activity specific attributes, it can be a useful means of scheduling to reduce the problem of promising the impossible.