Strategic Toolkit SYSTEM DYNAMICS · STOCK & FLOW

System Dynamics Diagnostic Tool

A physical and interactive workbench for stress-testing subscription economies. Map active stock reservoirs, isolate growth inflows from depletion sinks, analyze rate discrepancies, and trace cross-stock drain before systemic failure occurs.

Canvas SVG Reference SVG

1. Set The X Asset 2. Test IN: Growth Drivers & Shortage/Surge 3. Test OUT: Decay Sinks & Friction 4. Check Trajectory (IN vs OUT) 5. Laminated surface wipes clean with cloth

CATALYTICS · SYSTEM DYNAMICS TOOL

Stock & Flow Diagnostic Canvas · Cross-Stock Depletion & 2nd-Order Dynamics

A5 REUSABLE WORKBENCH Laminated · Dry-Erase Surface

TARGET SYSTEM / ASSET [X]:

OPERATOR / ANALYST:

DATE / CYCLE:

TIME HORIZON:

STEP 02 · INFLOW RATE

2. What makes it grow?

WHAT IF SHORTAGE?

Does it drain another stock?

Does it trigger a change?

WHAT IF ACCUMULATES?

Does it drain another stock?

Does it trigger a change?

Key Inflow Sources & Growth Drivers

STEP 01 · ACCUMULATOR

1. What is the X Asset?

THE X ASSET RESERVOIR

CURRENT STOCK LEVEL:

CRITICAL THRESHOLD:

What if IN < OUT? (Shortage / Depletion)

Stock empties; drains buffers towards zero.

What if IN = OUT? (Dynamic Equilibrium)

Stock remains stable; throughput cycle.

What if IN > OUT? (Accumulation / Expansion)

Stock expands; risk of bottleneck or lag.

Net Rate Delta (dStock/dt = IN - OUT)

STEP 03 · OUTFLOW RATE

3. What makes it smaller?

OUT

WHAT IF SHORTAGE?

Does it drain another stock?

Does it trigger a change?

WHAT IF ACCUMULATES?

Does it drain another stock?

Does it trigger a change?

Key Outflow Sinks & Decay Drivers

04 · PRIMARY FEEDBACK LOOP:

(+R) Reinforcing (-B) Balancing

HIGHEST-LEVERAGE INTERVENTION POINT:

CRITICAL SYSTEM DELAYS:

CATALYTICS · SYSTEM DYNAMICS REFERENCE

Field Guide to Systems Archetypes, Feedback Loops & Leverage Points

SIDE B · OPERATOR CHEAT SHEET A5 Reference Companion

COMMON SYSTEM ARCHETYPES IN DIGITAL PLATFORMS DIAGNOSTICS

01. FIXES THAT FAIL SHORT-TERM PATCH

A symptom is temporarily relieved by an intervention, but an unintended delay loop worsens the original problem.

Remedy: Decouple emergency fixes from root-cause fundamental solution.

02. SHIFTING THE BURDEN DEPENDENCE ADDICTION

Relying on external crutches (e.g. paid ad traffic, discounting) erodes internal organic retention capabilities.

Remedy: Strengthen core stock retention; systematically reduce external reliance.

03. LIMITS TO GROWTH CAPACITY BOTTLENECK

Accelerating reinforcing loop hits an unmodeled balancing constraint (support debt, billing processor friction).

Remedy: Remove the balancing limit BEFORE pouring fuel on acquisition.

04. SUCCESS TO THE SUCCESSFUL RESOURCE MONOPOLY

Two initiatives compete for the same stock; the early leader starves the other regardless of true systemic potential.

Remedy: Establish decoupled resource allocations and independent evaluation loops.

MATHEMATICS & LEVERAGE POINTS (DONELLA MEADOWS) FOUNDATIONS

THE ACCUMULATION LAW:

Stock(t) = Stock(t₀) + ∫ [ Inflow(s) − Outflow(s) ] ds

Stocks change only through continuous physical flows. You cannot change a stock instantly; you must modulate rates and absorb delays.

LEVERAGE POINTS (IN INCREASING ORDER OF POWER):

12–10. Parameters & Numbers: Price tweaks, ad bids, bonus amounts. (Lowest leverage)

09–07. Buffers & Delays: Stock reserve sizes, pacing of feedback signals, payment batch intervals.

06–04. System Structure & Information: Who sees what data when; positive/negative loop gains.

03–01. System Goals & Paradigms: The purpose of the system; metrics of value creation. (Highest leverage)

DEPLOY DIGITAL ENGINE: Run live fraud signals & Markov retention graphs. catalytics.online

How to Run Diagnostic Sessions with this Tool

Most teams fail because they optimize local flow variables while ignoring cross-stock depletion. Use this laminated canvas during sprint planning, architectural reviews, or post-mortems.

PROTOCOL 01

Isolate the True Accumulator

Name the physical stock in the center. Avoid vague KPIs — choose the concrete asset that accumulates over time (e.g. Active Paying Subscribers, Unsettled Cash Buffer, Fraud Risk Pool).

PROTOCOL 02

Stress-Test Cross-Stock Drain

Ask: "If Inflow drops to zero, where does the missing energy come from?" In digital subscription businesses, sudden acquisition slowdowns almost always silently drain customer trust, runway, or team morale.

PROTOCOL 03

Calibrate Rate Discrepancy

When IN < OUT, the stock is depleting. Identify the decay half-life. Don't attempt to solve the depletion by pouring more low-quality inflow into a leaky bucket; plug the outflow friction first.

PROTOCOL 04

Find Meadows' Leverage Point

Instead of tweaking parameters (spending more on bids or discounting), change information pathways. Give the payment engine real-time fraud scoring to prevent downstream chargeback catastrophe.