This structural pattern operates within a bounded system where material, energy, or information can be meaningfully accumulated and measured as discrete quantities. The pattern assumes that stocks have definable boundaries and that flows can be measured as rates over time. The dynamics focus on the accumulation mathematics where stock change equals inflow rate minus outflow rate, integrated over time.
Within the boundary are the stock-flow relationships, the delay dynamics that create system momentum, and the control mechanisms that regulate flows based on stock information. The pattern captures how delays between flow changes and stock changes create characteristic behaviors like overshoot, oscillation, and the inability to quickly change stock levels even when flows change rapidly.
Outside the boundary are the specific sources of inflows, destinations of outflows, and the broader purposes or goals that the stock-flow system serves. The pattern is also abstracted away from the specific physical, informational, or energy-based nature of what flows, focusing instead on the universal mathematical relationships and delay structures.