Double Diamond4 Phasen
Problem space (Discover fan -> Define waist) then solution space (Develop fan + prototype -> Deliver waist). Frame an ambiguous problem and take it to a buildable solution.
Wann: When you have a 'How Might We' question and want a rigorous problem framing plus a tested, buildable solution spec.
DiscoverDefineDevelopDeliver
Continuous Discovery4 Phasen
Teresa Torres' continuous discovery: weekly customer touchpoints feed an Opportunity Solution Tree (outcome -> opportunities -> solutions -> assumption tests). A repeating Interview (fan) -> Map opportunities (waist) -> Ideate (fan) -> Test assumptions (waist) loop that keeps a product team anchored to a desired outcome.
Wann: When discovery should be an ongoing habit, not a one-off project: you have a product outcome to move and want a steady cadence of small interviews and assumption tests rather than a single big study.
InterviewMap OpportunitiesIdeateTest Assumptions
Customer Discovery4 Phasen
Steve Blank's customer discovery run with The Mom Test interviewing discipline: Problem interviews (fan) -> Problem validation (waist) -> Solution interviews (fan) -> Pursue / pivot / drop (waist). Talk about the customer's real life and past behavior, never pitch the idea, and separate facts and commitments from compliments.
Wann: Early validation when you are not yet sure the problem is real or worth solving: interview honestly, find the problems that actually matter, then test whether a minimal solution earns genuine interest.
Problem InterviewsProblem ValidationSolution InterviewsPursue / Pivot / Drop
Design Sprint5 Phasen
Jake Knapp / GV five-act sprint compressed into one run: Map the problem (fan) -> Sketch competing solutions (fan) -> Decide on one concept and storyboard it (waist) -> Prototype a realistic facade (build) -> Test with users (waist). A timeboxed way to go from a hard question to a tested concept fast.
Wann: When you have a high-stakes question and want a tested answer quickly: align on the problem, generate competing concepts, pick one, prototype just enough to test, and get real reactions — all in one tight cycle.
MapSketchDecidePrototypeTest
Double Diamond (Deep)6 Phasen
The full design-thinking process as three linked diamonds: problem space (Discover broad -> Define key problems), solution exploration (Ideate broad + lo-fi -> down-select), solution refinement (mid-fi build -> Deliver tested solution presentation). Broad empathy, affinity clustering, and a lo-fi -> mid-fi fidelity ladder with real prototype tests.
Wann: When you want depth: many personas, broad problem exploration, clustered key problems, several lo-fi prototypes tested and down-selected, a refined mid-fi prototype tested, and a buildable solution presentation.
DiscoverDefineIdeate (Lo-Fi)Lo-Fi Test & Down-SelectRefine (Mid-Fi)Deliver (Solution Presentation)
JTBD Switch Interviews4 Phasen
Bob Moesta & Chris Spiek's Switch interview with Klement's four forces: Switch interviews (fan) -> Map the forces (waist) -> Shape the hire (fan) -> Validate the switch (waist). Reconstruct the timeline of a real recent switch and the push, pull, anxiety and habit around it to name the job a customer hires for.
Wann: When you want the causal story behind a purchase or switch: why people fired the old way and hired a new one, so you can design something that wins the switch.
Switch InterviewsMap the ForcesShape the HireValidate the Switch
Lean / Jobs-to-be-Done4 Phasen
Problem-explore (fan) -> Problem-pick (waist) -> Solution-explore (fan + prototype) -> Validate (waist). Lean-startup framing around the customer's job-to-be-done.
Wann: When you want to anchor on the customer's job, find the highest-value problem, then validate a minimal solution.
Problem ExploreProblem PickSolution ExploreValidate
Reaction Test2 Phasen
A lightweight reaction test for one fixed stimulus: collect audience reactions, then decide whether it clears a defined gate or needs revision.
Wann: Use when a concrete stimulus already exists and the decision is ship, revise, or review rather than broad discovery.
ReactGate
d.school Micro-Cycle4 Phasen
Stanford d.school micro-cycle: Understand/Observe (fan) -> Define POV (waist) -> Ideate (fan + prototype) -> Prototype & Test (waist).
Wann: Human-centered design when you want empathy-first divergence and rapid prototype testing.
Understand & ObserveDefine POVIdeatePrototype & Test