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Plan a concrete work block with agenda, roles, preparation, and a copyable result artifact.

Method session1-2 days initial, then refinementWorkshop or asyncStock and Flow Model

Session: Stock and Flow Diagram

The plan translates the method into a concrete facilitated work block. Your inputs flow directly into the session brief and work artifact.

Derived automatically

Method session with 1-6. The plan uses the existing method logic and the runsheet.

Runsheet
Participation logic
Team round, shared work and alignment

Use the session for shared understanding. Contributions are collected visibly, assumptions are aligned, and open differences remain traceable in the artifact.

Outcome logic
Finish artifact

The session works directly toward Stock and Flow Model. After the session, the artifact should be shareable, reviewable, or reusable.

  1. 1

    Phase 1: Identify stocks

    45 min

    Extract variables from CLD that are accumulations (stocks, balance, population). Define unit and current baseline per stock. Hint: Confusing stocks and flows is most common error. Rule of thumb: if world stops, a stock continues to exist (depends on past), flows are immediately zero.

    FacilitatorStock and Flow Model
  2. 2

    Phase 2: Assign flows

    60 min

    Define inflows and outflows per stock. Unit per time for each flow (for example signups/week). Mark source or sink as cloud if flow is external. Hint: If a flow has no unit per time, it is not a flow. Check mass balance: what enters must stay somewhere or leave somewhere.

    FacilitatorDynamics Notes
  3. 3

    Phase 3: Auxiliaries and relationships

    60 min

    Add auxiliary variables that influence flows (conversion rate, capacity, delay). Formulate relationships mathematically (Flow = Stock * Rate). Hint: Auxiliaries make models realistic. If flows depend directly on stocks, mechanism is missing. Make intermediate step explicit.

    FacilitatorSimulation Hypotheses
  4. 4

    Phase 4: Calibration with data

    2-4 h

    Feed model with reference-mode data. Adjust parameter values so simulation reproduces historical data (with acceptable deviation). Sensitivity analysis for critical parameters. Hint: If model does not explain past, it is unusable for future. Calibrate first, then forecast.

    FacilitatorStock and Flow Model
  5. 5

    Phase 5: Scenarios and interventions

    60-120 min

    Simulate several scenarios: baseline, intervention A, intervention B. Compare stock trajectories. Document effect after 3, 6, 12 months. Hint: Make delays visible. Some interventions show effect only after months, that is learning point, not model error.

    OwnerDynamics Notes
  6. 6

    Publish artifact

    10 min

    Check the artifact for completeness, define location, set version or status, and name review recipients.

    OwnerStock and Flow Model
Usable artifact

Session Brief

For invitations, boards, tickets, PR descriptions, or workshop notes.

session-brief.md

Session Brief: Stock and Flow Diagram

Goal

Artifact: Stock and Flow Model

Working Question

How does the central stock change over time, which flows and feedback loops drive behavior, and which intervention changes the dynamic structurally?

Context

Reference-mode data; CLD model; known constraints (capacities, budgets, contracts); historical interventions and their effect; hypotheses about delays.

Setup

  • Format: Method session
  • Duration: 1-2 days initial, then refinement
  • Mode: Workshop or async
  • Participants: One modeler experienced in system dynamics; domain expert with data knowledge; stakeholder with decision mandate; one reviewer for plausibility.
  • Owner: One modeler experienced in system dynamics
  • Participation mode: Team round, shared work and alignment
  • Outcome logic: Finish artifact

Participation Logic

Use the session for shared understanding. Contributions are collected visibly, assumptions are aligned, and open differences remain traceable in the artifact.

Outcome Logic

The session works directly toward Stock and Flow Model. After the session, the artifact should be shareable, reviewable, or reusable.

Input

Whiteboard or digital modeling tool (Stella, Vensim, Insight Maker); notation: stocks as boxes, flows as pipes with valve, clouds as source/sink; data snapshots; variable list with units.

Preparation

Install modeling tool or whiteboard with clear notation. Define units per variable (items, hours, EUR). Rule: stocks are states, flows are rates. No arrow without unit per time.

Agenda

  1. Phase 1: Identify stocks (45 min) Owner: Facilitator Action: Extract variables from CLD that are accumulations (stocks, balance, population). Define unit and current baseline per stock. Hint: Confusing stocks and flows is most common error. Rule of thumb: if world stops, a stock continues to exist (depends on past), flows are immediately zero. Output: Stock and Flow Model

  2. Phase 2: Assign flows (60 min) Owner: Facilitator Action: Define inflows and outflows per stock. Unit per time for each flow (for example signups/week). Mark source or sink as cloud if flow is external. Hint: If a flow has no unit per time, it is not a flow. Check mass balance: what enters must stay somewhere or leave somewhere. Output: Dynamics Notes

  3. Phase 3: Auxiliaries and relationships (60 min) Owner: Facilitator Action: Add auxiliary variables that influence flows (conversion rate, capacity, delay). Formulate relationships mathematically (Flow = Stock * Rate). Hint: Auxiliaries make models realistic. If flows depend directly on stocks, mechanism is missing. Make intermediate step explicit. Output: Simulation Hypotheses

  4. Phase 4: Calibration with data (2-4 h) Owner: Facilitator Action: Feed model with reference-mode data. Adjust parameter values so simulation reproduces historical data (with acceptable deviation). Sensitivity analysis for critical parameters. Hint: If model does not explain past, it is unusable for future. Calibrate first, then forecast. Output: Stock and Flow Model

  5. Phase 5: Scenarios and interventions (60-120 min) Owner: Owner Action: Simulate several scenarios: baseline, intervention A, intervention B. Compare stock trajectories. Document effect after 3, 6, 12 months. Hint: Make delays visible. Some interventions show effect only after months, that is learning point, not model error. Output: Dynamics Notes

  6. Publish artifact (10 min) Owner: Owner Action: Check the artifact for completeness, define location, set version or status, and name review recipients. Output: Stock and Flow Model

Closeout

  • Update result artifact: Stock and Flow Model
  • Define location, version, and review recipients.
  • Define owner, next step, and review date.
Usable artifact

Work artifact

Pre-filled starting point based on the matching template.

work-artifact.md

Stock and Flow Model: Stock and Flow Diagram

Working Question

How does the central stock change over time, which flows and feedback loops drive behavior, and which intervention changes the dynamic structurally?

Context

Reference-mode data; CLD model; known constraints (capacities, budgets, contracts); historical interventions and their effect; hypotheses about delays.

Participants

  • Owner: One modeler experienced in system dynamics
  • Participants: One modeler experienced in system dynamics; domain expert with data knowledge; stakeholder with decision mandate; one reviewer for plausibility.

Input

Whiteboard or digital modeling tool (Stella, Vensim, Insight Maker); notation: stocks as boxes, flows as pipes with valve, clouds as source/sink; data snapshots; variable list with units.

Template

Stock and Flow Diagram Canvas

Context

What is this method used for?

Core question

Which question should be answered at the end?

Input

Which data, observations, or materials are available?

Working area

  • Area 1:
  • Area 2:
  • Area 3:
  • Relationships / patterns:

Output artifacts

  • Stock and Flow Model:
  • Dynamics Notes:
  • Simulation Hypotheses:

Open questions

  • ...

Next step

Owner, date, success signal.

Completion Check

  • Stock and Flow Model is complete enough for review:
  • Location:
  • Version / status:
  • Review by:
  • Next step:

Next Step

  • Review result
  • Mark open questions
  • Schedule review or decision
Template base

Stock and Flow Diagram Working Template

View templateCompact working template for Stock and Flow Diagram with context, input, output artifacts, and next step.
canvas

stock-and-flow-diagram-working-template.md

Compact working template for Stock and Flow Diagram with context, input, output artifacts, and next step.

Stock and Flow Diagram Canvas

Context

What is this method used for?

Core question

Which question should be answered at the end?

Input

Which data, observations, or materials are available?

Working area

  • Area 1:
  • Area 2:
  • Area 3:
  • Relationships / patterns:

Output artifacts

  • Stock and Flow Model:
  • Dynamics Notes:
  • Simulation Hypotheses:

Open questions

  • ...

Next step

Owner, date, success signal.

Ready to use when
  • Working question, owner, and target artifact are visible.
  • The result fits Stock and Flow Model.
  • Version model as file in Git (XMILE format or tool-specific). One version per iteration, document changes to parameters or structure with rationale. Archive reference-mode data and simulation results separately.
  • Open questions are noted as follow-ups.
  • The next review or decision point is scheduled.
ProfileRunsheet