Approaches to capture complexity Flashcards
(22 cards)
What is a model?
A simplified representation of a system
What is a system?
A set of elements and relations
What are the two paradigms for understanding systems?
- Reductionist
- Complexity (systems thinking)
Define a complex system.
Interconnected individuals producing emergent system-level outcomes
What are systems models?
Simplified system descriptions using mathematical functions
What is an analytical model?
A model that can be ‘solved’ through symbolic manipulation
What is a simulation (numerical) model?
A model not ‘solved’ for an exact solution but used to approximate solutions
List some uses of systems models.
- Explain a phenomenon
- Test hypotheses
- Compare alternative strategies/policies
- Point out key uncertainties
- Teach
- Predict
What do agent-based models simulate?
Individual agents making decisions in a dynamic environment
Useful for modeling complex systems
What are the two main characteristics of agents in agent-based models?
Properties and Actions
Properties can be fixed or mutable; Actions include things that happen to them
What kind of rules are defined for agents in agent-based models?
Rules define how agents choose an action
Often defined stochastically
What type of time model do agent-based models typically use?
Discrete time models
Example: days
What types of environments can agent-based models represent?
Network, stylized locations, actual geographic space
Examples include hospitals, workplaces, homes, and GIS
What is a relative advantage of agent-based models?
They provide intuitions for the behavior of complex systems
Typically gained from direct observations
How can agent-based models help non-modelers?
By providing visualized simulations to confer understanding
This is difficult to achieve with equations
Fill in the blank: Agent-based models are a particular class of _______.
Computational models
Individual agents are simulated as explicit computational entities
What is an example of an action an agent might take in an infection model?
Become infected, move out of observation location, die
These actions illustrate how agents interact with their environment
True or False: Agent-based models can only simulate fixed properties of agents.
False
Agents can have both fixed and mutable properties
What are system dynamic models?
Aggregate models for computer simulation of a complex (adaptive) system
Feedback is a central concept
components that interact with one another in some way
Properties of a system dynamic model
*Components can have inputs, outputs, states, and functions
* Assumptions for relationships between components are made explicit (specified)
* Relationships between components can be modified to understand how the system will change with different or competing decisions
* Allows one to model the evolution of the system considering the inter-related components
* Can model evolution of the system over time (probabilistic dynamic system using Markov models)
* The endogenous point of view (a feedback system is a closed system) is a crucial foundation of the field of system dynamics
Systems dynamics practitioners use systems thinking, management insights, and computer simulation to:
- Hypothesize, test, and refine endogenous explanations of system change, and
- Use those explanations to guide policy and decision making
Why is thinking in systems important?
To be able to move scientific findings in practice and policy effectively and without too many unintended consequences we need to consider interactions, emergence, and interdependent parts rather than only think about the sum of parts as in reductionist thinking. It’s important to consider a complex worldview of a dynamic system of individual patient and population health care to recognize the place of one’s particular research area on the entire system.
