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Lean product development glossary

48 terms from R10, Lean product development — 27 defined in the guide itself and 21 more from the field around it. Every term the guide teaches links to the slide that teaches it.

The whole craft glossary

R10 · How to build

Lean product development

What is the smallest thing we can do to learn whether we are right?

Every term below is defined in the words of lean product development, guide R10 of craft guides for educational technologists, and opens the guide at the slide where it is taught. 21 of the 48 are the field’s vocabulary rather than the guide’s own: words a reader will meet around this subject, defined here because the guide assumes them. 3 terms are also defined by another guide in the series; where the two differ, both wordings are given. The whole craft glossary holds all of them together.

TermDefinitionReferred to inRead further
A
A3 report

A one-page account of a problem, its analysis, the proposed countermeasures and the follow-up plan, named after the paper size and used at Toyota to structure problem-solving and mentoring.

  • R10Lean product developmentFrom the field · not in the guide
  • Shook, J. (2008). Managing to learn: Using the A3 management process to solve problems, gain agreement, mentor, and lead. Lean Enterprise Institute.
Actionable metric

A measure that ties a specific, repeatable action to an observed result, so that a change in it tells the team what to do next. The opposite of a vanity metric.

  • R10Lean product developmentFrom the field · not in the guide
  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Schonfeld, E. (2011, September 24). Founder stories: Eric Ries on "vanity metrics" and "success theater". TechCrunch. techcrunch.com
Alpha phase

The delivery phase in which a team tries out different solutions to the problems found in discovery, tests its riskiest assumptions and expects to throw away the code (Government Digital Service, 2019).

  • Government Digital Service. (2019). How the alpha phase works. GOV.UK Service Manual. gov.uk
Assumption

A belief a plan depends on that has not yet been shown to be true.

  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
  • Gothelf, J., & Seiden, J. (2013). Lean UX: Applying lean principles to improve user experience. O'Reilly Media. oreilly.com
Assumptions mapping

Sorting a plan's beliefs by how important they are and how much evidence supports them (Bland, 2020).

  • Bland, D. J. (2020, August 4). How assumptions mapping can focus your teams on running experiments that matter. Strategyzer. strategyzer.com
  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
B
Build-measure-learn

The loop of turning an idea into something testable, measuring the response and deciding what to do next (Ries, 2011).

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Blank, S. (2013). Why the lean start-up changes everything. Harvard Business Review, 91(5), 63–72. hbr.org
Business model canvas

A one-page chart of nine blocks, including customer segments, value proposition, channels, revenue and costs, used to describe how an organisation creates and captures value and to list the assumptions behind it.

  • R10Lean product developmentFrom the field · not in the guide
  • Blank, S. (2013). Why the lean start-up changes everything. Harvard Business Review, 91(5), 63–72. hbr.org
  • Osterwalder, A., & Pigneur, Y. (2010). Business model generation: A handbook for visionaries, game changers, and challengers. Wiley.
C
Classroom floor

The minimum standard of learning, safety and consent that any test reaching students must meet. A term used in this guide.

  • British Educational Research Association. (2024). Ethical guidelines for educational research (5th ed.). bera.ac.uk
Concierge test

A test in which people openly deliver by hand what a product would later automate.

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
Cost of delay

What it costs to have a result or a feature later rather than sooner (Reinertsen, 2009).

R01 What it costs, per unit of time, to have a piece of work not yet done.

Customer development

Testing a business idea's hypotheses with potential users and buyers before building at scale (Blank, 2013).

  • Blank, S. (2013). Why the lean start-up changes everything. Harvard Business Review, 91(5), 63–72. hbr.org
  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
D
Desirability, feasibility and viability

Three kinds of assumption in a plan: whether teachers and students want it, whether the team can build and run it, and whether anyone will pay and keep paying (Bland & Osterwalder, 2019).

  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
  • Bland, D. J. (2020, August 4). How assumptions mapping can focus your teams on running experiments that matter. Strategyzer. strategyzer.com
Driver diagram

A one-page picture of an improvement team's working theory: the aim, the primary and secondary drivers believed to produce it, and the change ideas to be tested against each.

  • R10Lean product developmentFrom the field · not in the guide
  • Bryk, A. S., Gomez, L. M., Grunow, A., & LeMahieu, P. G. (2015). Learning to improve: How America's schools can get better at getting better. Harvard Education Press. books.google.com
F
Fake-door test

Offering a feature that does not yet exist and counting who tries to use it.

  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
Five whys

Asking 'why?' of a problem repeatedly, about five times, to get past its symptoms to a cause worth fixing.

  • R10Lean product developmentFrom the field · not in the guide
  • Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.
  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
Flow efficiency

The share of an item's total elapsed time during which someone is actually working on it, as opposed to it waiting in a queue.

  • R10Lean product developmentFrom the field · not in the guide
  • Modig, N., & Åhlström, P. (2012). This is lean: Resolving the efficiency paradox. Rheologica Publishing.
G
Gemba walk

A visit by managers to the place where the work is done, to watch it and ask questions there instead of relying on reports. Gemba is Japanese for 'the actual place'.

  • R10Lean product developmentFrom the field · not in the guide
  • Imai, M. (1997). Gemba kaizen: A commonsense, low-cost approach to management. McGraw-Hill.
  • Liker, J. K. (2004). The Toyota way: 14 management principles from the world's greatest manufacturer. McGraw-Hill.
H
Hypothesis statement

An assumption rewritten in testable form: we believe this outcome will follow if these users get this feature, and we will know we are right when we see this signal.

  • R10Lean product developmentFrom the field · not in the guide
  • Gothelf, J., & Seiden, J. (2013). Lean UX: Applying lean principles to improve user experience. O'Reilly Media. oreilly.com
  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
I
Improvement science

An approach to improving school systems through rapid cycles of Plan, Do, Study, Act, to learn fast, fail fast and improve quickly (Bryk et al., 2015).

  • Bryk, A. S., Gomez, L. M., Grunow, A., & LeMahieu, P. G. (2015). Learning to improve: How America's schools can get better at getting better. Harvard Education Press. books.google.com
  • Carnegie Foundation for the Advancement of Teaching. (n.d.). The six core principles of improvement. Retrieved September 17, 2026, from carnegiefoundation.org
Innovation accounting

A way of setting milestones and judging progress by what has been learned (Ries, 2011).

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
Innovation partnership

A public procurement route that runs in phases with intermediate targets and lets the buyer end the partnership after any phase (Directive 2014/24/EU, 2014).

  • Directive 2014/24/EU. (2014). Directive 2014/24/EU of the European Parliament and of the Council of 26 February 2014 on public procurement and repealing Directive 2004/18/EC. Official Journal of the European Union, L 94, 65–242. eur-lex.europa.eu
J
Just-in-time

Producing only what is needed, when it is needed and in the amount needed, so that unfinished work and stock do not pile up. One of the two pillars of the Toyota Production System.

  • R10Lean product developmentFrom the field · not in the guide
  • Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.
  • Womack, J. P., Jones, D. T., & Roos, D. (1990). The machine that changed the world. Rawson Associates. archive.org
K
Kaizen

Continuous improvement through many small changes proposed and tested by the people who do the work, rather than through occasional large redesigns.

  • R10Lean product developmentFrom the field · not in the guide
  • Imai, M. (1986). Kaizen: The key to Japan's competitive success. Random House.
  • Liker, J. K. (2004). The Toyota way: 14 management principles from the world's greatest manufacturer. McGraw-Hill.
Kanban

A method for managing work that makes it visible and limits how much is in progress (Anderson, 2010).

R09 A way of managing work that makes it visible on a board and limits how much is in progress at once (Anderson, 2010).

  • Anderson, D. J. (2010). Kanban: Successful evolutionary change for your technology business. Blue Hole Press. books.google.com
  • Reinertsen, D. G. (2009). The principles of product development flow: Second generation lean product development. Celeritas Publishing. lpd2.com
  • Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.
L
Last responsible moment

The point beyond which delaying a decision would close off an important option. Lean teams defer irreversible decisions until then, so they are made with the most information.

  • R10Lean product developmentFrom the field · not in the guide
  • Poppendieck, M., & Poppendieck, T. (2003). Lean software development: An agile toolkit. Addison-Wesley. informit.com
Lean canvas

An adaptation of the business model canvas for new products, which replaces some blocks with problem, solution, key metrics and unfair advantage.

  • R10Lean product developmentFrom the field · not in the guide
  • Maurya, A. (2012). Running lean: Iterate from plan A to a plan that works (2nd ed.). O'Reilly Media.
Lean start-up

An approach built on three practices: writing the business idea as hypotheses, testing them with customers outside the building, and building in small steps (Blank, 2013).

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Blank, S. (2013). Why the lean start-up changes everything. Harvard Business Review, 91(5), 63–72. hbr.org
  • Camuffo, A., Cordova, A., Gambardella, A., & Spina, C. (2020). A scientific approach to entrepreneurial decision making: Evidence from a randomized control trial. Management Science, 66(2), 564–586. doi
Lean thinking

Lean production reduced to five principles: value, the value stream, flow, pull and perfection (Womack & Jones, 1996).

  • Womack, J. P., & Jones, D. T. (1996). Lean thinking: Banish waste and create wealth in your corporation. Simon & Schuster. lean.org
  • Womack, J. P., Jones, D. T., & Roos, D. (1990). The machine that changed the world. Rawson Associates. archive.org
Little's law

In a stable system, average work in progress equals the arrival rate multiplied by the average time in the system (Little, 1961).

  • Little, J. D. C. (1961). A proof for the queuing formula: L = λW. Operations Research, 9(3), 383–387. doi
  • Reinertsen, D. G. (2009). The principles of product development flow: Second generation lean product development. Celeritas Publishing. lpd2.com
M
Minimum viable product

The version of a product that gets the most validated learning for the least effort (Ries, 2009).

  • Ries, E. (2009, August 3). Minimum viable product: A guide. Startup Lessons Learned. startuplessonslearned.com
  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Blank, S. (2013). Why the lean start-up changes everything. Harvard Business Review, 91(5), 63–72. hbr.org
Muda

Japanese for waste: any activity that uses resources without creating value for the user.

  • Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.
  • Womack, J. P., & Jones, D. T. (1996). Lean thinking: Banish waste and create wealth in your corporation. Simon & Schuster. lean.org
  • Lean Enterprise Institute. (n.d.). Seven wastes. Lean lexicon. Retrieved September 17, 2026, from lean.org
P
PDSA cycle

Plan, Do, Study, Act: the improvement cycle used in improvement science in education.

  • Bryk, A. S., Gomez, L. M., Grunow, A., & LeMahieu, P. G. (2015). Learning to improve: How America's schools can get better at getting better. Harvard Education Press. books.google.com
  • Carnegie Foundation for the Advancement of Teaching. (n.d.). The six core principles of improvement. Retrieved September 17, 2026, from carnegiefoundation.org
Pivot

A structured change of course to test a new fundamental hypothesis (Ries, 2011).

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Sadeghiani, A., & Anderson, A. R. (2023). What pivot is: Touching an elephant in the dark. Digital Business, 3(1), Article 100056. doi
  • Camuffo, A., Gambardella, A., Messinese, D., Novelli, E., Paolucci, E., & Spina, C. (2024). A scientific approach to entrepreneurial decision-making: Large-scale replication and extension. Strategic Management Journal, 45(6), 1209–1237. doi
Pretotype

A mock-up or pretence of a product, cheaper than a prototype, used to test whether people would want and use it before testing whether it can be built.

  • R10Lean product developmentFrom the field · not in the guide
  • Savoia, A. (2019). The right it: Why so many ideas fail and how to make sure yours succeed. HarperOne.
Pull system

A way of scheduling work in which a step starts a new item only when the step after it signals it has capacity, instead of work being pushed forward to a plan.

  • R10Lean product developmentFrom the field · not in the guide
  • Womack, J. P., & Jones, D. T. (1996). Lean thinking: Banish waste and create wealth in your corporation. Simon & Schuster. lean.org
  • Anderson, D. J. (2010). Kanban: Successful evolutionary change for your technology business. Blue Hole Press. books.google.com
R
Rapid-cycle evaluation

A quick, low-cost study, often a comparison run over weeks with data a school already holds, of whether an education technology is working well enough to keep, change or drop.

  • R10Lean product developmentFrom the field · not in the guide
  • Mathematica. (2017, January 24). Providing timely and reliable evidence for schools at no cost [News release]. mathematica.org
Riskiest assumption

The belief that is most important to the plan and least supported by evidence.

  • Bland, D. J., & Osterwalder, A. (2019). Testing business ideas: A field guide for rapid experimentation. Wiley. books.google.com
  • Bland, D. J. (2020, August 4). How assumptions mapping can focus your teams on running experiments that matter. Strategyzer. strategyzer.com
  • Government Digital Service. (2019). How the alpha phase works. GOV.UK Service Manual. gov.uk
S
Set-based design

Developing several design options in parallel and eliminating them gradually as evidence arrives, instead of choosing one early and reworking it. Also called set-based concurrent engineering.

  • R10Lean product developmentFrom the field · not in the guide
  • Poppendieck, M., & Poppendieck, T. (2003). Lean software development: An agile toolkit. Addison-Wesley. informit.com
  • Ward, A. C. (2007). Lean product and process development. Lean Enterprise Institute.
  • Morgan, J. M., & Liker, J. K. (2006). The Toyota product development system: Integrating people, process, and technology. Productivity Press.
T
Testbed

A real setting, such as a group of schools, where education technology is tried out and evaluated under everyday conditions, with teachers, developers and researchers working together.

  • R10Lean product developmentFrom the field · not in the guide
  • Batty, R., Florescu, A., Wong, A., & Sharples, M. (2019). EdTech testbeds: Models for improving evidence. Nesta. nesta.org.uk
Theory of constraints

The view that a system's output is limited by its single tightest bottleneck, so improvement anywhere else changes little until that constraint is relieved.

  • R10Lean product developmentFrom the field · not in the guide
  • Goldratt, E. M., & Cox, J. (1984). The goal: A process of ongoing improvement. North River Press.
Throughput

The number of work items a team or process finishes in a given period, such as tests completed per term.

  • R10Lean product developmentFrom the field · not in the guide
  • Anderson, D. J. (2010). Kanban: Successful evolutionary change for your technology business. Blue Hole Press. books.google.com
  • Reinertsen, D. G. (2009). The principles of product development flow: Second generation lean product development. Celeritas Publishing. lpd2.com
Toyota Production System

The factory system Toyota developed from the 1950s, which names seven kinds of waste, among them overproduction, waiting and inventory (Ohno, 1988).

  • Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.
  • Womack, J. P., Jones, D. T., & Roos, D. (1990). The machine that changed the world. Rawson Associates. archive.org
  • Krafcik, J. F. (1988). Triumph of the lean production system. Sloan Management Review, 30(1), 41–52.
V
Validated learning

Progress shown by evidence about users, rather than by what has been built.

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Ries, E. (2009, August 3). Minimum viable product: A guide. Startup Lessons Learned. startuplessonslearned.com
Value hypothesis

The assumption that people will find a product valuable once they use it. It is tested by watching what early users do, not by asking what they think.

  • R10Lean product developmentFrom the field · not in the guide
  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
Value stream mapping

Drawing every step, hand-off and wait between a request and its delivery, with the time each takes, to show where work sits idle and which steps add nothing.

  • R10Lean product developmentFrom the field · not in the guide
  • Womack, J. P., & Jones, D. T. (1996). Lean thinking: Banish waste and create wealth in your corporation. Simon & Schuster. lean.org
  • Rother, M., & Shook, J. (1999). Learning to see: Value-stream mapping to create value and eliminate muda. Lean Enterprise Institute.
Vanity metric

A number that rises with almost any activity and does not inform a decision, such as total logins.

  • Ries, E. (2011). The lean startup: How today's entrepreneurs use continuous innovation to create radically successful businesses. Crown Business. theleanstartup.com
  • Schonfeld, E. (2011, September 24). Founder stories: Eric Ries on "vanity metrics" and "success theater". TechCrunch. techcrunch.com
W
Wizard of Oz test

A test in which a hidden person simulates a system that users believe is automated (Kelley, 1984).

R07 A test in which a hidden person plays the part of a system (Kelley, 1984).

  • Kelley, J. F. (1984). An iterative design methodology for user-friendly natural language office information applications. ACM Transactions on Information Systems, 2(1), 26–41. doi
  • Dahlbäck, N., Jönsson, A., & Ahrenberg, L. (1993). Wizard of Oz studies: Why and how. Knowledge-Based Systems, 6(4), 258–266. doi
  • Kelley, J. F. (2018). Wizard of Oz (WoZ): A yellow brick journey. Journal of Usability Studies, 13(3), 119–124. uxpajournal.org
Work in progress (WIP)

Work that has started and not yet finished, including pilots with no decision yet.

  • Anderson, D. J. (2010). Kanban: Successful evolutionary change for your technology business. Blue Hole Press. books.google.com
  • Reinertsen, D. G. (2009). The principles of product development flow: Second generation lean product development. Celeritas Publishing. lpd2.com
  • Poppendieck, M., & Poppendieck, T. (2003). Lean software development: An agile toolkit. Addison-Wesley. informit.com

Nearby

The guide itself, and the ones either side

Read lean product development (opens in a new tab)Agile and Scrum in practice Software development for non-engineers All 21 guides
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