CPM: Early Calculations and Shortening the Critical Path
The manager should calculate the duration of the critical path frequently during the planning stages. So far the manager has done a lot of work, and possibly no useful output will result. The vice president might cancel the project.
The duration of the critical path might exceed a reasonable number of days. The Basic4 Corporation in 1971 needed a new file system; their system in those days could only handle file names of two characters. For unexplainable reasons, their system programmers took more than three years and Basic4 went out of business.
The cost of the project might exceed the budget. At the Federated Group, the cost of NCR cash registers was estimated above $500,000 per store. Some electronic retail chains like Circuit City and Silo were paying that much; in other words, if the store spends its profit on nothing but cash registers, nearly a whole year goes by.
The market changes. Pagers came and went; super-8 film came and went. Personal computers have changed.
Sierra Pacific suffered when the government changed the rules about depreciation and ruled that only active investors and not passive investors could write off depreciation.
The dynamics change within the business ; projects suffer when sponsors leave the business.
The duration of the critical path might exceed a reasonable number of days. The Basic4 Corporation in 1971 needed a new file system; their system in those days could only handle file names of two characters. For unexplainable reasons, their system programmers took more than three years and Basic4 went out of business.
The cost of the project might exceed the budget. At the Federated Group, the cost of NCR cash registers was estimated above $500,000 per store. Some electronic retail chains like Circuit City and Silo were paying that much; in other words, if the store spends its profit on nothing but cash registers, nearly a whole year goes by.
The market changes. Pagers came and went; super-8 film came and went. Personal computers have changed.
Sierra Pacific suffered when the government changed the rules about depreciation and ruled that only active investors and not passive investors could write off depreciation.
The dynamics change within the business ; projects suffer when sponsors leave the business.
Trimming the Critical Path
Several common techniques help to trim the critical path.
The Diagonal Method prospers from early and frequent releases, which tend towards early ROI and early feedback. The manager, therefore, looks for opportunities to find short routes from beginning to end. On rare occasion, the early delivery triggers bad feedback. How much better it is to get misunderstandings resolved earlier than later. At the AQMD, the bosses failed to heed early bad feedback about the Expansion Project; when the project failed, the bosses and many others lost jobs. At NEC, the generic inventory lookup changed weekly for months as the president and several key employees made suggestions and clarified subtleties.
Levels of Detail and Phases of Development
Once a project has a dozen or thirty tasks, the detail starts of overwhelm the viewer. We like to think that we have comprehensive--even encyclopedic--minds, but the fact of the matter is that we are all challenged. In the game of chess, few players can think more than two moves ahead. For shopping lists, people insist on paper or an Ipad after three or four items, especially if the items do not fit a nice sequence. The ingredients for spaghetti or for ham on rye sandwiches have patterns. Most lists do not and most people are distractible and somewhat absent minded.
Consequently, the manager should consider producing multiple levels of detail. The overall chart and the lesser charts.
see CPM Stem to Stern
Several common techniques help to trim the critical path.
- Better Tools -- at EDS, the spec said Microsoft C++, but the programmers used Borland C++ for development
- Better People -- I had good people, but I hired Dan Saylor at MMS and I hired Jack Howard at FG
- Eliminating Features
- Concurrent Actions -- The Continental Railroad started in St.Louis and in Sacramento at the same time; they met in Utah. Even though some process might require multiple programs, in some cases, those programs can be developed concurrently
- Phased-In Delivery of Programs -- Some essential programs come first; usually a year-end program is not needed until after the year ends.
- Phased-In Features -- Within a program, some features usually can wait; sometimes the clerk cannot learn all the features at once.
- Going with Plan B -- Sometimes the sponsor has an alternative plan
The Diagonal Method prospers from early and frequent releases, which tend towards early ROI and early feedback. The manager, therefore, looks for opportunities to find short routes from beginning to end. On rare occasion, the early delivery triggers bad feedback. How much better it is to get misunderstandings resolved earlier than later. At the AQMD, the bosses failed to heed early bad feedback about the Expansion Project; when the project failed, the bosses and many others lost jobs. At NEC, the generic inventory lookup changed weekly for months as the president and several key employees made suggestions and clarified subtleties.
Levels of Detail and Phases of Development
Once a project has a dozen or thirty tasks, the detail starts of overwhelm the viewer. We like to think that we have comprehensive--even encyclopedic--minds, but the fact of the matter is that we are all challenged. In the game of chess, few players can think more than two moves ahead. For shopping lists, people insist on paper or an Ipad after three or four items, especially if the items do not fit a nice sequence. The ingredients for spaghetti or for ham on rye sandwiches have patterns. Most lists do not and most people are distractible and somewhat absent minded.
Consequently, the manager should consider producing multiple levels of detail. The overall chart and the lesser charts.
see CPM Stem to Stern