The Lean Product Development book enumerates 175 principles in 8 categories: Economic, Queueing, Variability, Batch Size, WIP Constraint, Flow Control Fast Feedback and Decentralization…

Economic Principles

E1: The Principle of Quantified Overall Economics: Select actions based on quantified overall economic impact.
E2: The Principle of Interconnected Variables: We can’t just change one thing.
E3: The Principle of Quantified Cost of Delay: If you only quantify one thing, quantify the cost of delay.
E4: The Principle of Economic Value-Added: The value added by an activity is the change in the economic value of the work product.
E5: The Inactivity Principle: Watch the work product, not the worker.
E6: The U-Curve Principle: Important trade-offs are likely to have U-curve optimizations.
E7: The Imperfection Principle: Even imperfect answers improve decision making
E8: The Principle of Small Decisions: Influence the many small decisions
E9: The Principle of Continuous Economic Tradeoffs: Economic choices must be made continuously.
E10: The First Perishability Principle: Many economic choices are more valuable when made quickly.
E11: The Subdivision Principle: Inside every bad choice lies a good choice.
E12: The Principle of Early Harvesting: Create systems to harvest the early cheap opportunities.
E13: The Principle of Decision Rules: Use decision rules to decentralize economic control.
E14: The First Market Principle: Ensure decision makers feel both cost and benefit.
E15: The Principle of Optimum Decision Timing: Every decision has its optimum economic timing.
E16: The Principle of Marginal Economics: Always compare marginal cost to marginal value.
E17: The Sunk Cost Principle: Do not consider money already spent.
E18: The Principle of Buying Information: The value of information is its expected economic value.
E19: The Insurance Principle: Don’t pay more for insurance than the expected loss.
E20: The Newsboy Principle: High probability of failure does not equal bad economics.
E21: The Show Me the Money Principle: To influence financial decisions, speak the language on money.

Queueing Principles

Q1: The Principle of Invisible Inventory: Product development inventory is physically and financially invisible.
Q2: The Principle of Queueing Waste: Queues are the root cause of the majority of economic waste in product development.
Q3: The Principle of Queueing Capacity Utilization: Capacity utilization increases queues exponentially.
Q4: The Principle of High-Queue States: Most of the damage done by a queue is caused by high-queue states.
Q5: The Principle of Queueing Variability: Variability increases queues linearly.
Q6: The Principle of Variability Amplification: Operating at high levels of capacity utilization increases variability.
Q7: The Principle of Queueing Structure: Serve pooled demand with reliable high-capacity servers.
Q8: The Principle of Linked Queues: Adjacent queues see arrival or service time variability depending on loading.
Q9: The Principle of Queue Size Optimization: Optimum queue size is an economic tradeoff.
Q10: The Principle of Queueing Discipline: Queue cost is affected by the sequence in which we handle the jobs in the queue.
Q11: The Cumulative Flow Principle: Use CFDs to monitor queues.
Q12: Little’s Formula: Wait time = Queue Size/Processing Rate.
Q13: The First Queue Size Control Principle: Don’t control capacity utilization, control queue size.
Q14: The Second Queue Size Control Principle: Don’t control cycle time, control queue size.
Q15: The Diffusion Principle: Over time, queues will randomly spin seriously out of control and will remain in this state for long periods.
Q16: The Intervention Principle: We cannot rely on randomness to correct a random queue.

Variability Principles

V1: The Principle of Beneficial Variability: Variability can create economic value.
V2: The Principle of Asymmetric Payoffs: Payoff asymmetries enable variability to create economic value.
V3: The Principle of Optimum Variability: Variability should neither be minimized nor maximized.
V4: The Principle of Optimum Failure Rate: Fifty percent failure rate is usually optimum for generating information.
V5: The Principle of Variability Pooling: Overall variation decreases when uncorrelated random tasks are combined.
V6: The Principle of Short-Term Forecasting: Forecasting becomes exponentially easier at short time-horizons.
V7: The Principle of Small Experiments: Many small experiments produce less variation than one big one.
V8: The Repetition Principle: Repetition reduces variation.
V9: The Reuse Principle: Reuse reduces variability.
V10: The Principle of Negative Covariance: We can reduce variance by applying a counterbalancing effect.
V11: The Buffer Principle:Buffers trade money for variability reduction.
V12: The Principle of Variability Consequence: Reducing consequences is usually the best way to reduce the cost of variability.
V13: The Non-linearity Principle: Operate in the linear range of system performance.
V14: The Principle of Variability Substitution: Substitute cheap variability for expensive variability.
V15: The Principle of Iteration Speed: It is usually better to improve iteration speed than defect rate.
V16: The Principle of Variability Displacement: Move variability to the process stage where its cost is lowest.

Batch Size Principles

B1: Batch Size Queueing Principle: Reducing batch size reduces cycle time.
B2: The Batch Size Variability Principle: Reducing batch size reduces variability in flow.
B3: The Batch Size Feedback Principle: Reducing batch size accelerates feedback.
B4: The Batch Size Risk Principle: Reducing batch size reduces risk.
B5: The Batch Size Overhead Principle: Reducing batch size reduces overhead.
B6: The Batch Size Efficiency Principle: Large batches reduce efficiency. (
B7: The Psychology Principle of Batch Size: Large batches inherently lower motivation and urgency.
B8: The Batch Size Slippage Principle: Large batches cause exponential cost and schedule growth. (
B9: The Batch Size Death Spiral Principle: Large batches lead to even larger batches.
B10: The Least Common Denominator Principle of Batch Size: The entire batch is limited by its worst element.
B11: The Principle of Batch Size Economics: Economic batch size is a U-curve optimization.
B12: The Principle of Low Transaction Cost: Reducing transaction cost per batch lowers overall costs.
B13: The Principle of Batch Size Diseconomies: Batch size reduction saves much more than you think.
B14: The Batch Size Packing Principle: Small batches allow finer tuning of capacity utilization
B15: The Fluidity Principle: Loose coupling between product subsystems enables small batches.
B16: The Principle of Transport Batches: The most important batch is the transport batch.
B17: The Proximity Principle: Proximity enables small batch sizes.
B18: The Run Length Principle: Short run lengths reduce queues.
B19: The Infrastructure Principle: Good infrastructure enables small batches.
B20: The Principle of Batch Content: Sequence first that which adds value most cheaply.
B21: The Batch Size First Principle: Reduce batch size before you attack bottlenecks.
B22: The Principle of Dynamic Batch Size: Adjust batch size dynamically to respond to changing economics.

WIP Constraint Principles

W1: The Principle of WIP Constraints: Constrain WIP to control cycle time and flow.
W2: The Principle of Rate Matching: WIP constraints force rate-matching.
W3: The Principle of Global Constraints: Use global WIP constraints for predictable and permanent bottlenecks.
W4: The Principle of Local Constraints: If possible, constrain local WIP pools.
W5: The Batch Size Decoupling Principle: Use WIP ranges to decouple the batch sizes of adjacent processes.
W6: The Principle of Demand Blocking: Block all demand when WIP reaches its upper limit.
W7: The Principle of WIP Purging: When WIP is high, purge low value projects.
W8: The Principle of Flexible Requirements: Control WIP by shedding requirements.
W9: The Principle of Resource Pulling: Quickly apply extra resources to an emerging queue.
W10: The Principle of Part-Time Resources: Use part-time resources for high variability tasks.
W11: The Big Gun Principle: Pull high-powered experts to emerging bottlenecks.
W12: The Principle of T-Shaped Resources: Develop people who are deep in one area and broad in many.
W13: The Principle of Skill Overlap: Cross train resources at adjacent processes.
W14: The Mix Change Principle: Use upstream mix changes to regulate queue size.
W15: The Aging Principle: Watch the outliers.
W16: The Escalation Principle: Create a preplanned escalation process for outliers.
W17: The Principle of Progressive Throttling: Increase throttling as you approach the queue limit.
W18: The Principle of Differential Service: Differentiate quality of service by workstream.
W19: The Principle of Adaptive WIP Constraints: Adjust WIP constraints as capacity changes.
W20: The Expansion Control Principle: Prevent uncontrolled expansion of work.
W21: The Principle of the Critical Queue: Constrain WIP in the secion of the system where the queue is most expensive.
W22: The Cumulative Reduction Principle: Small WIP reductions accumulate.
W23: The Principle of Visual WIP: Make WIP continuously visible.

Flow Control Principles

F1: The Principle of Congestion Collapse: When loading becomes too high, we will see a sudden and catastrophic drop in output.
F2: The Peak Throughput Principle: Control occupancy to sustain high throughput in systems prone to congestion.
F3: The Principle of Visible Congestion: Use forecasts of expected flow time to make congestion visible.
F4: The Principle of Congestion Pricing: Use pricing to reduce demand during congested periods.
F5: The Principle of Periodic Resynchronization: Use a regular cadence to limit the accumulation of variance.
F6: The Cadence Capacity Margin Principle: Provide sufficient capacity margin to enable cadence.
F7: The Cadence Reliability Principle: Use cadence to make waiting times predictable.
F8: The Cadence Batch Size Enabling Principle: Use a regular cadence to enable small batch sizes.
F9: The Principle of Cadenced Meetings: Schedule frequent meetings using a predictable cadence. (
F10: The Synchronization Capacity Margin Principle: To enable synchronization, provide sufficient capacity margin.
F11: The Principle of Multiproject Synchronization: Exploit scale economies by synchronizing work from multiple projects.
F12: The Principle of Cross-Functional Synchronization: Use synchronized events to facilitate cross functional tradeoffs.
F13: The Synchronization Queueing Principle: To reduce queues, synchronize the batch size and timing of adjacent processes.
F14: The Harmonic Principle: Make nested cadences harmonic multiples.
F15: The SJF Scheduling Principle: When delay costs are homogeneous, do the shortest job first.
F16: The HDCF Scheduling Principle: When job durations are homogeneous, do the high cost-of-delay job first.
F17: The WSJF Scheduling Principle: When job durations and delay costs are not homogeneous, use WSJF.
F18: The Local Priority Principle: Priorities are inherently local.
F19: The Round-Robin Principle: When task duration is unknown, time-share capacity.
F20: The Preemption Principle: Only preempt when switching costs are low.
F21: The Principle of Work Matching: Use sequence to match jobs to appropriate resources.
F22: The Principle of Tailored Routing: Select and tailor the sequence of subprocesses to the task at hand.
F23: The Principle of Flexible Routing: Route work based on the current most economic route.
F24: The Principle of Alternate Routes: Develop and maintain alternate routes around points of congestion.
F25: The Principle of Flexible Resources: Use flexible resources to absorb variation.
F26: The Principle of Late Binding: The later we bind demand to resources, the smoother the flow.
F27: The Principle of Local Transparency: Make tasks and resources reciprocally visible at adjacent processes.
F28: The Principle of Preplanned Flexibility: For fast responses, preplan and invest in flexibility.
F29: The Principle of Resource Centralization: Correctly managed, centralized resources can reduce queues.
F30: The Principle of Flow Conditioning: Reduce variability before a bottleneck.

Fast Feedback Principles

FF1: The Principle of Maximum Economic Influence: Focus control on project and process parameters with the highest economic influence.
FF2: The Principle of Efficient Control: Control parameters that are both influential and efficient.
FF3: The Principle of Leading Indicators: Select control variables that predict future system behavior.
FF4: The Principle of Balanced Set Points: Set tripwires at points of equal economic impact.
FF5: The Moving Target Principle: Know when to pursue a dynamic goal.
FF6: The Exploitation Principle: Exploit unplanned economic opportunities.
FF7: The Queue Reduction Principle of Feedback: Fast feedback enables smaller queues.
FF8: The Fast Learning Principle: Use fast feedback to make learning faster and more efficient.
FF9: The Principle of Useless Measurement: What gets measured may not get done.
FF10: The First Agility Principle: We don’t need long planning horizons when we have a short turning radius.
FF11: The Batch Size Principle of Feedback: Small batches yield fast feedback.
FF12: The Signal to Noise Principle: To detect a smaller signal, reduce the noise.
FF13: The Decision Rule Principle: Control the economic logic behind the decision, not the entire decision.
FF14: The Locality Principal of Feedback: Whenever possible make feedback local.
FF15: The Relief Valve Principle: Have a clear, predetermined relief valve.
FF16: The Principle of Multiple Control Loops: Embed fast control loops inside slow loops.
FF17: The Principle of Controlled Excursions: Keep deviations within the control range.
FF18: The Feedforward Principle: Provide advance notice of heavy arrival rates to minimize queues.
FF19: The Principle of Colocation: Colocation improves almost all aspects of communications.
FF20: The Empowerment Principle of Feedback: Fast feedback gives a sense of control.
FF21: The Hurry-Up-and-Wait Principle: Large queues make it hard to create urgency.
FF22: The Amplification Principle: The human element tends to amplify large excursions.
FF23: The Principle of Overlapping Measurement: To align behaviors, reward people for the work of others.
FF24: The Attention Principle: Time counts more than money.

Decentralization Principles

D1: The Second Perishability Principle: Decentralize control for problems and opportunities that age poorly.
D2: The Scale Principle: Centralize control for problems that are infrequent, large, or that have significant economies of scale.
D3: The Principle of Layered Control: Adapt the control approach to emerging information about the problem.
D4: The Opportunistic Principle: Adjust the plan for unplanned obstacles and opportunities.
D5: The Principle of Virtual Centralization: Be able to quickly reorganize decentralized resources to create centralized power.
D6: The Inefficiency Principle: The inefficiency of decentralization can cost less than the value of faster response time.
D7: The Principle of Alignment: There is more value created with overall alignment than local excellence.
D8: The Principle of Mission: Specify the end state, its purpose, and the minimal possible constraints.
D9: The Principle of Boundaries: Establish clear roles and boundaries.
D10: The Main Effort Principle: Designate a main effort and subordinate other activities.
D11: The Principle of Dynamic Alignment: The main effort may shift quickly when conditions change.
D12 The Second Agility Principle: Develop the ability to quickly shift focus.
D13: The Principle of Peer-Level Coordination: Tactical coordination should be local.
D14: The Principle of Flexible Plans: Use simple modular plans.
D15: The Principle of Tactical Reserves: Decentralize a portion of reserves.
D16: The Principle of Early Contact: Make early and meaningful contact with the problem.
D17: The Principle of Decentralized Information: For decentralized decisions, disseminate key information widely.
D18: The Frequency Response Principle: We can’t respond faster than our frequency response.
D19: The Quality of Service Principle: When response time is important, measure response time.
D20: The Second Market Principle: Use internal and external markets to decentralize control.
D21: The Principle of Regenerative Initiative: Cultivating initiative enables us to use initiative.
D22: The Principle of Face-to-Face Communication: Exploit the speed and bandwidth of face-to-face communications.
D23: The Trust Principle: Trust is built through experience.

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