Skip to content
PM Master Handbook ⬇ PDF
Library

Framework Library

29 frameworks, each with a visual model, worked example, usage criteria, limitations and a reusable template.

30 entries
Guide

Framework selection guide: which framework should I use?

Match your product problem to the right framework, and know when not to use one.

Strategy

SWOT

Strengths, weaknesses (internal), opportunities, threats (external) — then turn them into actions.

Strategy

PESTLE

Scan the macro environment — Political, Economic, Social, Technological, Legal, Environmental.

Strategy

Porter's Five Forces

Assess industry attractiveness via rivalry, entrants, substitutes, buyer and supplier power.

Strategy

Business Model Canvas

Nine blocks describing how an organisation creates, delivers and captures value.

Strategy

Value Proposition Canvas

Fit customer jobs, pains and gains with your products, pain relievers and gain creators.

Metrics

North Star Framework

One metric that captures recurring customer value, broken into input drivers with guardrails.

Strategy

OKRs (Objectives and Key Results)

A qualitative objective with 2–4 measurable key results; initiatives are bets to move them.

Discovery

Jobs to Be Done (JTBD)

People "hire" products to make progress in a specific situation; understand the job, not the demographic.

Discovery

Customer Journey Mapping

Visualise a persona's stages, actions, thoughts, emotions, touchpoints and pain points end to end.

Discovery

Opportunity Solution Tree

Connect a desired outcome to customer opportunities, candidate solutions and the experiments that test them.

Design

Design Thinking

Empathise, define, ideate, prototype, test — an iterative, human-centred problem-solving approach.

Design

Double Diamond

Discover and define the right problem, then develop and deliver the right solution — diverge, converge, twice.

Discovery

Lean Startup

Reduce waste by testing business hypotheses with MVPs, validated learning and pivot-or-persevere decisions.

Discovery

Build–Measure–Learn

The Lean Startup feedback loop — minimise total time through the loop.

Prioritization

RICE

Reach × Impact × Confidence ÷ Effort — compare comparable initiatives with explicit estimates.

Prioritization

ICE

Impact × Confidence × Ease (1–10 each) — fast ranking, popular for growth experiments.

Prioritization

MoSCoW

Must, Should, Could, Won't (this time) — negotiate scope for a fixed release or time-box.

Prioritization

Kano Model

Classify features as must-be, performance, attractive, indifferent or reverse based on satisfaction.

Prioritization

Weighted Prioritization (Scoring)

Score options against weighted strategic criteria and compare totals.

Prioritization

Cost of Delay

Quantify the value lost per unit of time by not having something — make urgency explicit.

Prioritization

WSJF (Weighted Shortest Job First)

Cost of Delay ÷ job size, using relative scores — favours small, urgent, valuable work.

Metrics

AARRR (Pirate Metrics)

Acquisition, Activation, Retention, Revenue, Referral — diagnose where growth leaks.

Metrics

HEART

Google's UX metrics framework — Happiness, Engagement, Adoption, Retention, Task success — with Goals → Signals → Metrics.

Experimentation

Hypothesis Testing

State a null hypothesis, set α in advance, compute a test statistic and p-value, report the effect with a confidence interval.

Experimentation

A/B Testing

Randomly assign users to control and variant, compare a pre-registered metric with guardrails.

Problem solving

Five Whys

Ask "why?" repeatedly to move from a symptom toward a systemic cause — verifying each step with evidence.

Problem solving

Pareto Analysis

Sort causes by frequency (or impact) and focus on the vital few that drive most of the effect.

Problem solving

First Principles Thinking

Break a problem into fundamental truths and rebuild the solution, instead of reasoning by analogy.

Problem solving

Systems Thinking

Map feedback loops, delays and side effects so you don't optimise one metric while breaking another.

Framework selection guide: which framework should I use?

Frameworks are thinking tools: they organise evidence and make reasoning visible. They never replace evidence or judgement. Start from the decision you need to make, then pick the lightest framework that helps.

If your question is…Reach forWhyAvoid
Who is the customer and what are they trying to get done?JTBD, Customer Journey MapFrames demand around progress in a situationDemographic personas alone
Which customer problem should we pursue for our outcome?Opportunity Solution TreeLinks outcome → opportunities → solutions → testsJumping to features
Is our idea worth pursuing at all?Lean Startup / Build-Measure-Learn, assumption testingCheapest test of riskiest assumptionBuilding the full product first
What should we build first?RICE / ICE (comparable items); WSJF (time-critical)Explicit, comparable scoringScores as facts; ignoring dependencies
What fits in this release?MoSCoWScope negotiation against a dateRanking within a category
Which features delight vs are expected?KanoCustomer expectation categoriesSmall or unsegmented samples
Choose among few strategic betsWeighted scoring, Cost of DelayEncodes strategic criteria and urgencyReverse-engineered weights
Where are we in the market? Should we enter?SWOT, PESTLE, Porter's Five ForcesStructured environment scanLists without so-what
How does our business create and capture value?Business Model Canvas, Value Proposition CanvasMakes the model and fit explicitTreating cells as facts
What single metric aligns the team?North Star Framework (+ metric tree), OKRsFocus with drivers and guardrailsOne metric without guardrails
Where is the growth funnel leaking?AARRRStage-by-stage diagnosisGeneric definitions
How do we measure UX quality?HEARTGoals → signals → metricsTracking all five by default
Did the change work?Hypothesis testing, A/B testingCausal evidence with uncertaintyUnderpowered tests; peeking
Why did this happen?Five Whys, fishbone, ParetoRoot causes and focusSingle-chain blame
Are we stuck in assumptions or loops?First principles, systems thinkingRebuild from fundamentals; see feedback loopsOver-theorising simple issues
How should we explore a fuzzy problem?Design Thinking, Double DiamondDiverge then converge with usersWorkshops without real users
Given this problem, which framework?. Start from the decision. If a framework doesn't change what you would do, skip it.

Decision tree in words: Unclear problem? → discovery frameworks (JTBD, journey, OST, Design Thinking). Clear problem, many options? → prioritisation (RICE/ICE/WSJF/MoSCoW/Kano). Strategic direction? → SWOT/PESTLE/Porter/canvases. Measuring? → North Star, AARRR, HEART, OKRs. Proving causality? → hypothesis and A/B testing. Something broke? → Five Whys, fishbone, Pareto.

Interview tip

Name a framework only after you have clarified the problem, then use it (show a few real scores or boxes) and state its limitation. Interviewers reward applied judgement, not vocabulary.

SWOT

Strengths (internal, helpful)
  • Capabilities, assets, advantages
Weaknesses (internal, harmful)
  • Gaps, constraints, liabilities
Opportunities (external, helpful)
  • Trends, unmet needs, partners
Threats (external, harmful)
  • Competitors, regulation, cost shifts
SWOT model. Follow with TOWS: S×O (use strengths to seize), W×O (fix to seize), S×T (use strengths to defend), W×T (avoid).

Use when: framing a strategy discussion, market entry, annual planning. Don't use when: you need prioritised actions or quantified trade-offs — SWOT alone produces lists.

Worked example (hypothetical): regional food-delivery entrant — S: restaurant relationships; W: small marketing budget; O: office-lunch subscriptions; T: incumbents' promo wars. TOWS action: S×O → launch office-lunch subscriptions through existing restaurant partners; W×T → don't compete on discounts.

Limitations: subjective, static, often evidence-free; items mix levels of importance. Always attach evidence and rank items.

Template: for each quadrant list ≤ 5 items, each with evidence and importance (H/M/L); then write 3 TOWS actions with owners. Deep dive: Module 2.

PESTLE

Political
  • Government policy, stability, trade
Economic
  • Rates, inflation, income, demand
Social
  • Demographics, behaviour, trust
Technological
  • Infrastructure, platforms, AI
Legal
  • Data protection, consumer law, licensing
Environmental
  • Climate, sustainability expectations
PESTLE model. Mark each factor as tailwind or headwind, rate impact × certainty, and assign a watcher.

Use when: entering a new market or country; long-range planning; regulated products. Don't use when: you need customer-level insight (use research) or competitor detail (use competitor analysis).

Worked example (hypothetical): fintech lending in a new market — Legal: data-protection consent and lending disclosures (high impact, high certainty → design consent flows early); Technological: digital ID infrastructure (tailwind → faster KYC); Economic: rising interest rates (headwind → stricter credit policy).

Limitations: can become a long list with no prioritisation; factors interact; needs expert input for legal/regulatory items. Template: factor · description · tailwind/headwind · impact (1–5) · certainty (1–5) · implication · owner. Deep dive: Module 2.

Porter's Five Forces

Use when: deciding whether to enter a market, explaining margin pressure, positioning against structural threats. Don't use when: analysing a single feature, or in fast-changing ecosystems without considering complements and platforms.

Worked example (hypothetical): food delivery — rivalry high (promotions), buyer power high (low switching costs), supplier power medium–high (restaurants multi-home), substitutes high (cooking, dining out), entrants medium (density is hard). Implication: invest in habit/loyalty (reduce buyer power) and partner tools (reduce supplier churn).

Limitations: static snapshot; industry boundaries are fuzzy; ignores network effects and complementors. Template: force · rating (L/M/H) · evidence · trend · product lever. Deep dive: Module 2.

Business Model Canvas

Key partners
  • Who helps us?
Key activities
  • What must we do well?
Value propositions
  • What value for whom?
Customer relationships
  • How do we relate?
Customer segments
  • For whom?
Key resources
  • What do we need?
Channels
  • How do we reach them?
Cost structure
  • Major costs
Revenue streams
  • How we earn
Business Model Canvas (structure). Fill right side (customers, value) first; then left (how you deliver); then costs and revenue.

Use when: describing or redesigning a business model; comparing models; onboarding stakeholders to the economics. Don't use when: you're still searching for a problem (use Lean Canvas) or need financial detail (build a model).

Worked example: see the meal-planning app canvas in Module 2. Limitations: static; doesn't show competition or sequencing; cells are assumptions until tested. Template: the nine headings with assumption / evidence / test for each cell. Deep dive: Module 2.

Value Proposition Canvas

Value map: Products & services
  • What we offer
Customer profile: Jobs
  • Functional, emotional, social jobs
Value map: Pain relievers
  • How we remove pains
Customer profile: Pains
  • Obstacles, risks, frustrations
Value map: Gain creators
  • How we create gains
Customer profile: Gains
  • Outcomes and benefits sought
Value Proposition Canvas (structure). Fit = your relievers and creators address the most important pains and gains (ranked by customers, not by you).

Use when: shaping a new offering or repositioning; aligning product and marketing on what matters. Don't use when: you have no customer research yet — the right side would be guesses.

Worked example (hypothetical): busy parents — job: feed the family on budget; top pain: surprise grocery bills; reliever: price estimate before shopping; gain creator: weekly budget tracker. Test: smoke test with the promise “Know your weekly grocery cost in 5 minutes”.

Limitations: easy to fill with assumptions; doesn't capture competition. Template: rank top 3 jobs, pains, gains with evidence; map each reliever/creator to a ranked pain/gain. Deep dive: Module 2.

North Star Framework

Use when: aligning several teams on a shared outcome; moving from output to outcome culture. Don't use when: a product has distinct, unrelated value streams (use separate goals) or the metric can't be measured reliably yet.

Worked example (hypothetical): food app NSM = completed problem-free orders per active customer per month; inputs = activation, order frequency, payment success, on-time delivery; guardrails = refund rate, complaint rate.

Limitations: can be gamed (Goodhart's law); one metric never tells the whole story; may need revisiting as strategy changes. Template: NSM definition (numerator, denominator, window) · why it reflects value · 3–5 input metrics with owners · 2–3 guardrails · review cadence. Deep dive: Module 7.

OKRs (Objectives and Key Results)

Use when: quarterly focus and alignment; outcome-based planning. Don't use when: as a task list, an individual performance score, or with 10+ objectives.

Worked example: O: make checkout trustworthy for first-time buyers. KR1: completion 70% → 76% (new users). KR2: payment-failure recovery 20% → 35%. KR3 (guardrail): complaint rate ≤ 1.3%. Initiatives: early fee display; payment retry.

Limitations: sandbagging or unrealistic stretch; metric gaming; overhead. Template: Objective · KRs (metric, baseline, target, date, owner) · initiatives · weekly confidence score (0–10). Deep dive: Module 2.

Jobs to Be Done (JTBD)

Job statement
  • When [situation], I want to [motivation], so I can [expected outcome].
Push (away from today)
  • Frustrations with the current way
Pull (toward new)
  • Attraction of the new solution
Anxiety (about new)
  • Fears and uncertainties
Habit (of today)
  • Inertia, sunk costs, routines
JTBD model — job statement and the four forces. Switching happens when push + pull > anxiety + habit.

Use when: discovering demand; understanding competition broadly (including non-consumption); positioning. Don't use when: you need usability detail (use testing) or market sizing.

Worked example (hypothetical): When I'm in back-to-back meetings with 15 minutes to eat, I want a filling lunch at my desk without surprise costs, so I can stay focused and on budget. Competitors: snacks, colleagues, skipping lunch. Implication: reliability and price clarity beat variety.

How to run: interview recent switchers about the timeline of their decision (first thought → passive looking → active looking → decision → first use); map forces; write 2–4 job statements; validate frequency with data.

Limitations: interpretive; job statements can become vague slogans; needs good interviewing. Template: job statement · situation triggers · desired outcomes (measurable) · current alternatives · push/pull/anxiety/habit evidence. Deep dive: Module 3.

Customer Journey Mapping

Use when: aligning teams on the end-to-end experience; finding cross-channel gaps (app + support + delivery). Don't use when: you need screen-level flow detail (use a user flow) or have no research to base it on.

Worked example (hypothetical): weekday dinner journey — lowest points at “cart total” (fee surprise) and “support” (slow refunds). Opportunities: show total early; proactive refund status.

Limitations: can become a beautiful poster nobody uses; averages hide segment differences. Template: columns = stages; rows = actions, thoughts/quotes, emotion score, touchpoints, pains, opportunities, owners, metrics. Deep dive: Modules 3 and 5.

Opportunity Solution Tree

Use when: continuous discovery with a clear outcome; avoiding solution-first thinking; communicating why you're working on something. Don't use when: you lack an agreed outcome, or the work is mandatory (compliance).

Worked example: outcome = checkout completion 70% → 76%; opportunities: fee surprise, payment-failure dead ends, long first-order form; solutions and tests as in Module 3.

Limitations: requires ongoing research to stay true; can grow unwieldy. Template: outcome · opportunities (from interviews, with evidence) · ≥ 3 solutions per chosen opportunity · assumption tests. Deep dive: Module 3.

Design Thinking

Use when: ambiguous problems, new experiences, cross-functional workshops. Don't use when: the problem and solution are well understood and the risk is delivery, not discovery.

Worked example: checkout redesign — empathise (interviews: fee surprise) → define (“first-time buyers can't see total before paying”) → ideate (8 concepts) → prototype (2 Figma variants) → test (6 users; task success 50% → 83%).

Limitations: workshops without real users become theatre; can neglect business viability and feasibility. Template: problem statement · research insights · how-might-we questions · concepts · prototype plan · test tasks · learnings. Deep dive: Module 5.

Double Diamond

Use when: planning a discovery-to-delivery project and explaining to stakeholders why time goes into problem definition. Don't use when: for small iterative changes.

Worked example: a fintech onboarding project spends 3 weeks in Discover (interviews, funnel analysis), converges on “document upload fails on low-end phones,” then explores 5 solutions and delivers camera guidance + save-and-resume.

Limitations: looks linear; real work loops. Template: for each diamond: activities, outputs, decision gate, owner. Deep dive: Module 5.

Lean Startup

Validated learning
  • Progress = what you learned with evidence
MVP
  • Smallest experiment to test a key assumption
Innovation accounting
  • Baseline → tune → measure progress on actionable metrics
Pivot or persevere
  • Change strategy based on evidence, not ego
Actionable vs vanity metrics
  • Cohort-based, causal metrics over totals
Small batches
  • Ship small, learn fast
Lean Startup principles. Popularised by Eric Ries (The Lean Startup, 2011).

Use when: high uncertainty about customer, problem, solution or business model. Don't use when: in highly regulated or safety-critical contexts where an “MVP” cannot be released without full assurance (use prototypes and simulations instead).

Worked example: meal-planning app — leap-of-faith assumptions: parents plan weekly; trust price estimates; will pay ₹1,200/yr. MVP sequence: fake door (demand) → concierge (value) → priced pilot (willingness to pay). Pivot if pilot conversion < 3%.

Limitations: misread as “ship low quality”; startup framing may not fit enterprise constraints. Template: assumptions ranked by risk · experiment per assumption · success threshold · decision. Deep dive: Module 4.

Build–Measure–Learn

Use when: iterating toward fit; structuring sprints around learning goals. Don't use when: measurement is impossible within a useful time frame (use qualitative tests instead).

Worked example: learn whether early fee display reduces surprise → measure task success in 6 usability sessions and later checkout completion in an A/B test → build a two-screen prototype, then a flagged feature.

Limitations: “Build” first framing can encourage building before learning; loops need clear decision rules. Template: learning question · metric and threshold · smallest build · result · decision (pivot/persevere/stop). Deep dive: Modules 4 and 7.

RICE

RICE = Reach × Impact × Confidence ÷ Effort Impact scale: 3 massive · 2 high · 1 medium · 0.5 low · 0.25 minimal Confidence: 100% high · 80% medium · 50% low Effort: person-months (> 0)

Use when: many comparable items, some data on reach. Don't use when: comparing mandatory work, platform investments with diffuse reach, or items with unknowable impact.

Worked example: fee early = 40,000 × 2 × 0.8 ÷ 2 = 32,000; voice ordering = 8,000 × 2 × 0.3 ÷ 8 = 600 (see Module 4 for all six and the stakeholder script).

Limitations: false precision; bias toward high-reach items; confidence is subjective. Template: feature · reach (unit, period, source) · impact (scale + rationale) · confidence (evidence) · effort (eng estimate) · score · notes on dependencies/risks. Deep dive: Module 4.

ICE

Use when: quick triage of experiment ideas with similar audiences. Don't use when: reach varies widely (use RICE) or decisions are high-stakes and need more rigour.

Worked example: fee early I8 × C8 × E7 = 448; voice I7 × C3 × E2 = 42.

Limitations: very subjective; easy to game; ignores reach and dependencies. Template: idea · hypothesis · I (why) · C (evidence) · E (effort note) · score · owner. Deep dive: Module 4.

MoSCoW

Must
  • Release fails without it
Should
  • Important, painful to omit
Could
  • Nice if time allows
Won't (this time)
  • Explicitly out of scope
MoSCoW model. Agree the release period and why each item sits where it does.

Use when: fixed-date releases, contract scope, MVP definition. Don't use when: ranking many items against each other (it doesn't order within categories).

Worked example: early-fee release — Must: estimate + labels + fallback; Should: refresh on address change; Could: “add ₹X to avoid fee” nudge; Won't: fee-policy change.

Limitations: “Must” inflation; no numeric basis. Guideline: keep Musts to roughly 60% or less of capacity. Template: item · category · rationale · owner · dependency. Deep dive: Module 4.

Kano Model

Use when: deciding what makes a competitive baseline vs a differentiator; planning releases that balance basics and delight. Don't use when: you lack enough respondents per segment, or need cost/feasibility trade-offs.

Worked example: payment confirmation = must-be; faster checkout = performance; surprise free dessert = attractive; dark mode = indifferent for most, performance for night-shift users.

Limitations: survey wording sensitivity; categories shift; ignores cost. Template: feature · functional question · dysfunctional question · answer distribution · category (see the evaluation table in Module 4). Deep dive: Module 4.

Weighted Prioritization (Scoring)

Score = Σ (weight_i × score_i) weights sum to 100%

Use when: choosing among a few strategic initiatives where criteria differ from pure reach/effort. Don't use when: weights are set after seeing scores, or with too many criteria.

Worked example: payment retry 5×.35 + 4×.25 + 4×.20 + 3×.20 = 4.15 (Module 4 has all four).

Limitations: subjective scores; hides trade-offs inside a total. Test sensitivity by shifting weights ±10 points. Template: criteria + weights (agreed first) · anchored 1–5 scales · scores with rationale · total · sensitivity notes. Deep dive: Module 4.

Cost of Delay

Cost of Delay = value per unit time × delay CD3 = Cost of Delay ÷ duration (do highest first)

Use when: arguing for capacity, sequencing time-sensitive work, comparing urgent vs important. Don't use when: value per time can't be estimated even roughly.

Worked example: a 6-week delay of a ₹50,000/week feature costs ₹3,00,000 — compared with the ₹1,20,000 cost of a contractor to accelerate it.

Limitations: estimates are uncertain; urgency profiles differ. Template: item · value/week (range) · urgency profile · expected delay · CoD · duration · CD3. Deep dive: Module 4.

WSJF (Weighted Shortest Job First)

WSJF = (User/business value + Time criticality + Risk reduction/opportunity enablement) ÷ Job size

Use when: scaled-agile planning with many teams and competing epics. Don't use when: job sizes are unknown or political.

Worked example: C: (5 + 13 + 2) ÷ 3 = 6.67; B: (13 + 8 + 5) ÷ 13 = 2.0 — the small urgent fix goes first.

Limitations: relative scores are subjective; can starve big strategic work. Template: job · value · time criticality · RR/OE · CoD · size · WSJF. Deep dive: Module 4.

AARRR (Pirate Metrics)

Use when: diagnosing a growth problem; organising a metrics dashboard; growth-team planning. Don't use when: applied with generic definitions — each stage must be defined for your product.

Worked example: activation (42%) and 30-day retention (45% of activated) are the biggest levers; improving activation by 5 points adds ~500 activated users/month at the same acquisition spend.

Limitations: linear view of a non-linear journey; ignores user value quality; no guardrails by default. Template: stage · event definition · metric · current · target · owner · top hypothesis. Deep dive: Module 7.

HEART

DimensionGoalSignalMetric
HappinessUsers find search satisfyingPost-search ratingAvg rating; % positive
EngagementUsers rely on searchSearches per active userWeekly searches per user
AdoptionNew users try searchFirst search% new users searching in week 1
RetentionUsers keep searchingRepeat search% searchers searching again next week
Task successUsers find what they wantClick/add-to-cart after searchSearch success rate; time to result
HEART with Goals–Signals–Metrics (example: search feature). Pick the dimensions that match your goal; you rarely need all five.

Use when: defining UX success for a feature or redesign. Don't use when: you need business-outcome metrics only (pair with North Star/AARRR).

Worked example: checkout redesign — Task success (completion rate, errors), Happiness (CSAT), Adoption (first-time buyer completion).

Limitations: survey-based happiness is noisy; engagement can conflict with wellbeing. Template: dimension · goal · signal · metric · baseline · target. Deep dive: Module 5.

Hypothesis Testing

z = (p₂ − p₁) ÷ √[ p̂(1 − p̂)(1/n₁ + 1/n₂) ], p̂ = (x₁ + x₂)/(n₁ + n₂) p-value = P(result at least this extreme | H₀ true)

Use when: deciding whether an observed difference is likely to be more than noise. Don't use when: samples are tiny, assignment isn't random, or you're fishing across many metrics without correction.

Worked example: 7,000/10,000 vs 7,250/10,000 → z = 3.91, p ≈ 0.00009, 95% CI +1.25 to +3.75 pts (Module 7).

Limitations: p-values are widely misread (not the probability the variant works); significance ≠ importance. Template: H₀/H₁ · α · test · sample size/power · result (effect, CI, p) · decision. Deep dive: Module 7.

A/B Testing

Use when: enough traffic, reversible change, measurable short-term outcome. Don't use when: low traffic, strong network effects/contamination, legal or safety changes, or long-horizon outcomes.

Worked example: sizing for 70% → 72% at α 0.05 and 80% power: ≈ 8,077 users per arm (Module 7).

Limitations: novelty effects, interference between users, multiple-testing false positives, only measures what you instrument. Template: hypothesis · population · variants · primary metric · guardrails · MDE · n per arm · duration · analysis plan · decision rule. Deep dive: Module 7.

Five Whys

Use when: post-incident reviews, recurring defects, metric drops. Don't use when: problems have many interacting causes (use fishbone/systems thinking) or the exercise turns into blame.

Worked example: late orders → riders wait → food not ready → optimistic prep estimates → estimates ignore kitchen load → add live load signal (Module 4).

Limitations: single causal chain; depends on knowledge in the room. Template: problem · why 1–5 with evidence · root cause · countermeasure · owner · verification. Deep dive: Module 4.

Pareto Analysis

Use when: many issues compete for attention; support or defect triage. Don't use when: severity varies hugely (weight by impact, not count) or categories are poorly defined.

Worked example: fixing late delivery and wrong items addresses 60% of complaints; but payment failures may be more severe per case — weight by cost or harm before deciding.

Limitations: “80/20” is a heuristic, not a law; frequency ≠ importance. Template: category · count · % · cumulative % · severity weight · owner. Deep dive: Module 4.

First Principles Thinking

Use when: stuck in incremental thinking; cost structures seem fixed; designing something new. Don't use when: the problem is routine and well-solved — conventions (Jakob's law) exist for good reasons.

Worked example: “30-minute delivery promise because competitors promise it” → fundamentals: customers want reliability; costs are travel and wait → promise an honest live-load window instead.

Limitations: time-consuming; risk of ignoring hard-won conventions. Template: goal · assumption list · evidence for each · which are real constraints · new design options. Deep dive: Module 4.

Systems Thinking

Use when: metrics move in unexpected directions; marketplaces; growth tactics with side effects; policy changes. Don't use when: a simple, isolated bug (use Five Whys).

Worked example: surge pricing increases supply (reinforcing for availability) but raises cancellations and mistrust (balancing) — add caps and fare transparency.

Limitations: diagrams can become complex; hard to quantify. Template: variables · links (+/−) · loops (R/B) · delays · leverage points · guardrail metrics. Deep dive: Module 4.