Analysis Tools Used Throughout Development
There are many
task analysis tools available to support human-centered design.
These tools are used to define, evaluate, and document function
and task flows throughout development. They are iteratively
addressed and refined, providing a visual, graphic representation
that is used to focus discussion and decisions on system design.
The task analysis tools that will be addressed in this section are:
Functional Flow Diagrams, Flow Process Charts (FPC), Decision/Action
Diagrams, Operational Sequence Diagrams (OSDs), and Human Error
Flow Diagrams - Also referred to as functional block diagrams,
functional flows, and functional flow block diagrams, these diagrams
graphically depict system functions and the sequence and interrelationships
of these functions. Initial diagrams are high level and
do not include function allocation. As design efforts progress,
levels of detail are added such as function allocation, data/information
interchange, frequency, and timing. Arrows indicate the normal
sequence of functions. Reference block numbering indicates
the function level and association for traceability as functions
are decomposed. Points at which arrows join or split are
connected by "and," "or," or "and/or"
junctions or gates.
Below is a graphical
explanation of a function "block" used in these diagrams.
Flow is from left to right. Functional flow diagrams are decomposed
into multiple levels of finer detail. On the next page, three-levels
of a functional flow diagram are presented for illustrative purposes.