the collection of some quantity over time the incorporation of numerous distinct system components into one variable

1. accumulation

the collection of some quantity over time

2. aggregation

the incorporation of numerous distinct system components into one variable. It is done for simplicity when combination generates the same behavior of interest as representing the components separetely

3. amplification

a system response that is greater than is seemingly implied by input causes. it occurs in information-feedback systems when policies adjust levels to values that change with varying flow rates. it is associated with delays, order/inventroy processes, forecasting, etc

4. asymptotic growth/decay

goal-seeking behavior produced by negative feedback. the stock of the system moves towards the goal, slowing down as it approaches the goal

5. auxiliary equation/variable

an equation that takes the present value of variables (levels, constants, or other auxilary vairables) to compute the present value of an auxiliary variable. They are part of a rate equation connecting a level to a rate. They embody unit consistency and are symbolized by a circle in a flow equation

6. balancing loop

a loop that seeks equilibrium - it tries to bring stocks to a desired stated and keep them there. it limits and constrains, and is also called a negative loop. when a balancing process has a long delay, the response may overcorrect, often leading to instability, the opposite of what is intended

7. the Beer Game

a 'laboratory replica' of a real organization that involves a production/distribution system. The players at each position make decisions about placing orders, and find from practice the problems that originate from traditional ways of thinking and interaction

8. behavior over time diagram

a system dynamics tool that shows how certain variable change over time. Several variables can appear on the same graph for comparison

9. boundary

border enclosing only the parts of system structure needed to generate the behavior of interest. in other words, the system boundary excludes all components not relevant to the problem behavior of the system.

10. casual loop diagram

diagram representing a closed loop of cause-effect linkages (causal links) which is intended to capture how the variables interrelate. the five steps of constructing a causal loop diagram are 1) choose variables 2) link variables with arrows pointing from cause to effect 3) assign a direction of effect (same or opposite) to each link 4) indicate delays 5) assign polarity overall loop