System Characteristics, System States, Characteristic Indicator
Continuing from these posts, I’d like to reflect on the relationship between the following concepts: system characteristic (or subject of interest), system state, and characteristic indicator. While these are all covered in systems thinking courses, confusion often arises in practice.
A system characteristic is a stable, long-term property that determines how the system functions as a whole. For example, load capacity, controllability, reliability, efficiency, and scalability are universal characteristics that describe the behavior of various systems—whether a vehicle, an organization, or a software product. Each type of system also has its own unique characteristics. These characteristics do not change instantly and set the boundaries for the possible states of the system or its ability to perform certain functions (play roles).
Take a vehicle, for instance: its load capacity or controllability determines which functions it can perform. A vehicle with high off-road capability can serve as a tow truck; one with a spacious cargo area can act as a truck; and one with a large cabin can even serve as a dwelling. Focusing on system characteristics helps you choose the right system model depending on the task. For example, if you need to transport people, priorities include safety, durability, and so on. If the goal is to win races, attention shifts to speed, acceleration, and aerodynamics.
In contrast, the state of a system is the configuration of the system that changes over time during operation. It reflects the current situation and changes under the influence of internal and external factors. For example, a vehicle can be in a state of motion, parking, braking, emergency, overheating, or towing. The vehicle itself remains the same (with the same characteristics and functions), but at different moments during operation, its states differ.
If a vehicle is stuck in the mud and being towed, it temporarily cannot fulfill its main role as a means of transportation. This is another example of how the state of a system affects its ability to carry out its inherent functions. However, unlike system characteristics, which describe the overall ability of an agent to perform certain functions, system states are more about the current ability to fulfill already understood roles.
Monitoring states plays a key role in system operation. For example, engine temperature, oil level, and tire-road grip are indicators of a vehicle’s state that help make real-time operational decisions. If tire grip deteriorates due to ice, the driver adapts their driving style. If the engine overheats, it’s necessary to either stop or reduce the load.
In addition to system characteristics and states, it’s also important to consider the concept of a “characteristic indicator.” This is the specific quantitative value of a characteristic in a given system state. For example, a vehicle has the characteristic of maneuverability, but in the state of “driving on ice,” its indicator might be 50%, while in the state of “driving on dry pavement,” it could be 90%. This explains why the same system can demonstrate different levels of effectiveness under different conditions. For example, a person may have high endurance, but if they haven’t slept well, their ability to handle prolonged exertion will be lower.
The concept of “indicator” can be used to link the “value of a characteristic” and the “unit of measurement.” In this case:
- Characteristic – a general property of the system (for example, speed, mass, temperature).
- Indicator – the characteristic expressed as a specific value and measured in a particular unit (for example, 90 km/h, 50 kg, 36.6 °C, though it’s not always a numerical value).
- Unit of measurement – the standard in which the indicator is expressed (for example, km/h, kg, °C).
- Indicator value – the numerical value of the characteristic in the given unit of measurement (for example, 90, 50, 36.6).
Let’s look at a few examples:
- Vehicle:
- Characteristic: speed
- Indicator: 90 km/h
- Indicator value: 90
- Unit of measurement: km/h
- Person
- Characteristic: body temperature
- Indicator: 36.6 °C
- Indicator value: 36.6
- Unit of measurement: °C
- Phone
- Characteristic: memory capacity
- Indicator: 256 GB
- Indicator value: 256
- Unit of measurement: GB
Quite often, an indicator is a characteristic expressed as a numerical value tied to a unit of measurement. However, some characteristics may have qualitative rather than quantitative indicators. For example, body type—sedan, hatchback, SUV; fuel type—gasoline, diesel, electric.
In summary, system characteristics are its long-term properties that determine its potential capabilities. The state of a system is its current configuration, which depends on various conditions and can change rapidly. A characteristic indicator is a measurable value that reflects how much a characteristic is manifested in a given state.