dependency (project management)

In a project network, a dependency is a link amongst a project's terminal elements. There are four kinds of dependencies with respect to ordering terminal elements (in order of decreasing frequency of use):

Finish to start (FS)

A FS B = B doesn't start before A is finished
(Foundations dug) FS (Concrete poured)

Finish to finish (FF)

A FF B = B doesn't finish before A is finished
(Entire book written) FF (Last chapter written)

Start to finish (SF)

A SF B = B doesn't finish before A starts
(New shift started) SF (Previous shift finished)

Start to start (SS).

A SS B = B doesn't start before A starts
(Project work started) SS (Project management activities started)

There are three kinds of dependencies with respect to the reason for the existence of dependency:

Causal (logical)

It is impossible to edit a text before it is written
It is illogical to pour concrete before you dig the foundations

Resource constraints

It is logically possible to paint four walls in a room simultaneously but there is only one painter

Discretionary

I want to paint the living room before painting the dining room, although I could do it the other way round, too

Traditional critical path-derived schedules are based only on causal (logical) dependencies. The critical chain method necessitates taking into account resource constraint-derived dependencies as well.

Dependency (Project Management)

See also