Comparison of Schedule Managing Methods
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| − | Projects involve many different tasks that must be done to complete the project. Many of these tasks will in construction projects logically depend on each other. For example, it is necessary to build supporting walls or columns before the roof can be installed. There are several methods to keep track of these dependencies. In this article three similar methods will be explained and their differences will be compared together with their pros and cons. The three methods compared in this article are the critical path method (CPM), the critical chain method (CCM) and critical space analysis (CSA). | + | Projects involve many different tasks that must be done to complete the project. Many of these tasks will in construction projects logically depend on each other. For example, it is necessary to build supporting walls or columns before the roof can be installed. There are several methods to keep track of these dependencies. In this article three similar methods will be explained and their differences will be compared together with their pros and cons. The three methods compared in this article are the critical path method (CPM), the critical chain method (CCM) and critical space analysis (CSA). |
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The critical path method works by dividing a project into smaller tasks. The duration for these tasks are estimated by either comparing similar tasks in earlier projects or by asking those who are in charge of the specific task. These duration estimates naturally have some amount of uncertainty; however, this uncertainty is not considered in the critical path method. This uncertainty either must be accepted or considered externally with the use of probabilistic methods. When the tasks are defined and the durations are specified, the tasks can be put into a schedule. The schedule is made so that tasks that needs other tasks to finish beforehand are put in a path. The longest duration of the paths then defines the critical path and thereby the shortest execution time of the project. | The critical path method works by dividing a project into smaller tasks. The duration for these tasks are estimated by either comparing similar tasks in earlier projects or by asking those who are in charge of the specific task. These duration estimates naturally have some amount of uncertainty; however, this uncertainty is not considered in the critical path method. This uncertainty either must be accepted or considered externally with the use of probabilistic methods. When the tasks are defined and the durations are specified, the tasks can be put into a schedule. The schedule is made so that tasks that needs other tasks to finish beforehand are put in a path. The longest duration of the paths then defines the critical path and thereby the shortest execution time of the project. | ||
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The critical path method does not take resources into account when calculating the shortest execution time. For this, other methods can be used such as the critical chain method. This method takes labour and equipment into account. The critical chain in the project is calculated similarly to the critical path method however this method calculated the longest resource-constrained path. | The critical path method does not take resources into account when calculating the shortest execution time. For this, other methods can be used such as the critical chain method. This method takes labour and equipment into account. The critical chain in the project is calculated similarly to the critical path method however this method calculated the longest resource-constrained path. | ||
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In small construction sites with limited space the workers may not be able to work effectively simultaneously. The critical space analysis addresses this issue by using the available space as a resource similarly to the critical chain method. The fastest execution time of the project then depends on reduced effectiveness of the work. | In small construction sites with limited space the workers may not be able to work effectively simultaneously. The critical space analysis addresses this issue by using the available space as a resource similarly to the critical chain method. The fastest execution time of the project then depends on reduced effectiveness of the work. | ||
Revision as of 10:14, 9 June 2017
Projects involve many different tasks that must be done to complete the project. Many of these tasks will in construction projects logically depend on each other. For example, it is necessary to build supporting walls or columns before the roof can be installed. There are several methods to keep track of these dependencies. In this article three similar methods will be explained and their differences will be compared together with their pros and cons. The three methods compared in this article are the critical path method (CPM), the critical chain method (CCM) and critical space analysis (CSA).
The critical path method works by dividing a project into smaller tasks. The duration for these tasks are estimated by either comparing similar tasks in earlier projects or by asking those who are in charge of the specific task. These duration estimates naturally have some amount of uncertainty; however, this uncertainty is not considered in the critical path method. This uncertainty either must be accepted or considered externally with the use of probabilistic methods. When the tasks are defined and the durations are specified, the tasks can be put into a schedule. The schedule is made so that tasks that needs other tasks to finish beforehand are put in a path. The longest duration of the paths then defines the critical path and thereby the shortest execution time of the project.
The critical path method does not take resources into account when calculating the shortest execution time. For this, other methods can be used such as the critical chain method. This method takes labour and equipment into account. The critical chain in the project is calculated similarly to the critical path method however this method calculated the longest resource-constrained path.
In small construction sites with limited space the workers may not be able to work effectively simultaneously. The critical space analysis addresses this issue by using the available space as a resource similarly to the critical chain method. The fastest execution time of the project then depends on reduced effectiveness of the work.
