EARS Flashcards
The “ubiquitous” requirement meaning and template
active at all times
the {system name} shall {system response}
The car shall have a maximum retail sale price of XXX
The “event-driven” requirement meaning and template
initiated after some triggering event detected
WHEN {trigger} the {system name} shall {system response}
When the clutch pedal is depressed, the car shall disengage the driving force
The “state-driven” requirement meaning and template
is continuously active but only in a given state
WHILE {in specific state} the {system name} shall {system response}
While the ignition is on, the car shall display the fuel level and the oil level to the driver
The “option” requirement meaning and template
typically ubiquitous but only for systems that include a specified feature
WHERE {feature is included} the {system name} shall {system response}
Where the car has electric windows, the electric window controls shall be on the driver’s door panel
The “unwanted” requirement meaning and template
how the system responds when a typically undesirable or unwanted condition arises or unwanted trigger is detected
IF {optional condition} {trigger}, THEN the {system name} shall {system response}
If the car detects attempted intrusion, then the car shall operate the car alarm
4 strengths of EARS
- provides rigor and consistency
- easy to learn and apply
- no tools needed
- common form of requirements communication
2 weaknesses of EARS
- limited inter-requirement coupling
- unsuitable for very complex requirements
