Best alternative & economic life

8.1 Proposal Relationships

Independent proposal & dependent proposal
Forms of dependency

• Co-dependent.
• Mutually exclusive.
• Contingent

8.2 Dependent Proposals

Co-Dependent Proposals

when selecting any one from that set requires accepting the others.

• These should be combined into one proposal
• e.g., Specific programming language VS Its compiler

Mutually Exclusive Proposals

A pair of proposals are mutually exclusive, when selecting one from that pair negates accepting the other.

• These should be combined into one proposal.

Contingent Proposals

A pair of proposals are contingent, when selecting one from that pair requires accepting the other, but not the other way / reverse direction.

8.3 Design Alternative: mutually exclusive units

steps

1.List alternatives
2.Remove invalid alternatives

“Do Nothing” Alternative

Alternative A0 is called “Do nothing”
"Do nothing" should always be considered, except when

• You’re required to do something
  e.g., repair or replace broken equipment.
• You’re working with “new project” (without income)