Some businesses that use project management software like the Critical Path Method (CPM) should also take the time to learn about the much less well known Critical Chain Project Management technique as it has a proven track record for dramatically speeding up projects.
Maybe you follow the Path
It is possible that you use computer software like Critical Path Method (CPM) to identify the correct sequence of events to undertake in a project.
By way of example, CPM might be used to plan out the construction of a home. It indicates what has to be done, in what order and how long each element of the project may take.
When this is all added together in CPM, the computer will indicate the most time-sensitive aspects of The Project and draw what's known as a Critical Path. The builder knows they have to focus on the Critical Path to get the job done in the least possible time.
However, CPM has been shown to be quite a poor predictor of the best way of undertaking a project and very often will lead to a greatly extended project.
The principal reason for this is that, when people are asked to estimate how long it will take to do a job, they inevitably overestimate the length of time required to give themselves a safety margin. Their bosses probably allow a bit of "safety" as well. The result is the time estimated to be required for any element of the project is greatly inflated.
When all these inflated times are added together, the period required to complete the project is also greatly inflated.
Individuals have no real incentive to finish the job before the date given to have a project, or their section of a project, completed, They will tend to leave their start to the last moment (the School Homework problem; homework tends to get left to the last moment).
They might even get penalized by being given more work if they finish early. Parkinson's Law that work will expand the time available means there can also be unnecessary "embroidery" to fill in any time left over (see Parkinson's Law article)
But should follow the Constraint
An alternative approach, known as Critical Chain Program Management (CCPM) was developed from the Theory of Constraints school of management (see Theory of Constraints (TOC) article).
Time is only one constraint in a project and is not really a strong constraint because usually you can just take longer to get the job done if necessary.
But, more specifically, a true constraint is the time a critical resource has for that part of a project.
If your house needs an electrician, they can only do one thing at a time so they will be a constraint on any project stage that needs an electrician.
Sometimes, to compensate for being a constraint, the resource will slip into multitasking but this is likely to worsen rather than improve the situation (See Multitasking Tool article).
CCPM focuses on having components of a project arrive at the various resources required to do them just when they are ready. They then exclusively focus on getting that done until completed.
There has been analysis that suggests CCPM can finish projects 30-40% faster than CPM.
Because project planning is such an import part of some industries like software, there are other project management techniques like Scrum and Agile that have grown up to address the problem of time slippage in project management.
If you do a lot of project management, those other techniques might also have something to offer.
Links to other resources for more learning.
Books There are several books written in the business novel style which makes them easy to follow; if somewhat light on detail. See e.g. the first book on the subject by the inventor Eli Goldratt; "The Chain". Others will appear in context in Amazon when you search for this one.