The purpose of a project management methodology is so that at every level during the course of a project, a certain approach is taken. This not only includes the processes that are working, but also the handling of the risks and issues that a project might encounter along the way.
Many businesses use the same project management methodology they have always used. In many cases this is sufficient to get the job done and the deliverable out the door and into the hands of the customer. Unfortunate this has not always been the case.
After the end of WWII, Japan had few men and even fewer resources in which to create a deliverable. The project management methodology that was used before and during the war no longer was available to them. This is when the original lean methodology was born. This was out of necessity because more had to be done with less.
The manufactures had to look at every process and remove or eliminate everything that did not contribute to the quality or sell ability of the deliverable. With this review of all the process, anything that was waste would no longer be a part of the project. This was all done manually with all the process being hand written because at this time there were no computers or project management methodology programs for them to use.
Today the business world has project management template programs that make this process significantly faster and easier. The templates can be a guide and help document all the changes that would be necessary to complete this arduous task.
Because there was no guide to this new project management methodology many items were overlooked. For decades the quality of products coming out of Japan was suspect. With the age of computers also came a higher level of quality. Some contribute this to the use of project management software programs while others just think it was hard work and perseverance of the people in Japan.