Project managers would use the critical path method’s (CPM) as the duration of the entire project by raising its duration to add extra time to the schedule if needed in case of any delay on a task or job to predict further delays which could really affect the project’s finalization.
But of course those extra time added, had the wrong impact on the schedule. That is where the upgraded, the latest version of the critical path intervened. The critical chain was created.
Critical chain is the upgraded version focused on the resources (workers, equipment etc.) needed to complete the project. These resources focus would apparently decrease the duration of the project completion.
In critical path (CPM), you don’t gain by adding extra time because you only add the delay. Finishing an activity early or earlier does nothing, as you can’t start the next activity before its start time.
Float can also be misused in critical path (CPM) and lead to the student syndrome. Because, as workers feel that the activity has added time, believe they can start later than the start time. Using the added time of the activity as a sign of, I can start later.
So, even though critical path method (CPM) may seem longer in terms of added delays and non-advancements and critical chain focuses on a realistic schedule by really thinking of the uncertainties of the job in a project. It is the preparations and adding buffers at the end of every activity for critical chain that draws out the project management. You have to make sure the buffers are correctly added. It is the process that can take longer than that of the critical path.
To conclude, it seems like there is no true winner here between critical chain and critical path of a project. Furthermore, it depends on the size and complexity of the project and the company’s organization. But that does not mean that critical path and critical chain is not a help when it comes to estimate duration of an activity or project, budget cost and resources available, which are the main things for a successful project.
If you start by sorting it out all the essentials for the project, it starts with a good beginning, leading to a fruitful project.