Lean vs. Agile vs. Scrum vs. Kanban: A Comparability

Over the previous three many years, Agile-inspired frameworks similar to Scrum, Kanban, Excessive Programming (XP), and Lean-Agile have come to dominate software program growth. Whereas they share a lineage, every provides a distinct strategy to managing software program growth tasks—and every has distinct benefits and limitations.

On this challenge administration blueprint, I talk about the Lean and Agile philosophies and hint their discursive evolution and utilized apply from auto-manufacturing in mid-Twentieth-century Japan to their present-day use by software program groups worldwide, adopted by an in depth examination of Scrum and Kanban, the 2 most prevalent Agile-inspired frameworks within the trade right now.

Lean Philosophies

The time period “Lean” developed from the Toyota Production System (TPS), a producing mannequin developed by Sakichi Toyoda, Kiichiro Toyoda, and Taiichi Ohno. The system revolutionized manufacturing from the Nineteen Fifties to the Seventies by specializing in eliminating inefficiencies from the manufacturing course of. Toyota recognized three broad sources of inefficiency:

1. Waste: Waste (recognized in Japanese as muda) arises because of defects, overproduction, ready, transport, inventories, movement, and extra processing. (Many corporations now acknowledge unused talent as an eighth sort of waste.)

2. Overburden: Overburden (muri) applies to personnel and equipment and manifests as burnout, absenteeism, or issues of safety. To stop muri, Toyota distributed manufacturing actions evenly throughout the meeting line.

3. Unevenness: Unevenness (mura) may result from fluctuating buyer demand or variations in operator pace or product completion instances. It will increase the chance of overburden, creating waste. Coaching employees on a number of machines for elevated flexibility and forecasting demand can assist cut back unevenness.

To take away these impediments, Toyota established its manufacturing system on a core idea generally known as “just-in-time.” This strategy minimizes the retention of extra inventory previous to manufacturing. As a substitute, the corporate replenishes supplies as merchandise are accomplished in what’s generally known as a “pull system.”

Toyota acknowledged that high quality management have to be ingrained within the manufacturing course of, requiring each automation and human intelligence—a mix known as jidoka. Toyota designed equipment to cease robotically when an issue occurred. The corporate additionally empowered employees to cease manufacturing once they seen irregularities.

TPS emphasizes the need of steady enchancment, on-the-ground statement, and respect for folks by teamwork and collaboration. Toyota’s philosophy and practices have been additional popularized within the 1990 e book The Machine That Changed the World by James P. Womack, Daniel T. Jones, and Daniel Roos, which cited TPS because the mannequin for “Lean manufacturing.”

Lean Developments

Lean rules started coming into software program growth within the Nineteen Nineties. At that time, the trade was in determined want of latest approaches. A 1994 report by the Standish Group discovered that fewer than one in 5 software program tasks have been an unqualified success. These deficiencies have been partly because of conventional Waterfall methodologies, which outlined necessities at first of multiyear tasks and resulted in late or over-budget software program supply. In some circumstances, the deliverables have been out of date because of market adjustments that had occurred throughout a challenge.

Early enhancements to Waterfall included rapid application development, which emerged at IBM and unfold with the publication of James Martin’s 1991 e book Rapid Application Development. This technique centered on waste discount through strategies similar to speedy prototyping. Software program builders additionally moved towards incremental growth, including options in a continuing iteration of small tasks. Whereas these methods of working helped, they didn’t resolve the core issues related to Waterfall.

One other important growth occurred throughout the realm of enterprise administration. In 1996, authors James P. Womack and Daniel T. Jones adopted up on The Machine That Modified the World with Lean Thinking. The e book outlined the rules of Lean management, distilling the core Lean values of steady enchancment and respect for folks into 5 prescriptive rules that may very well be used to remove waste and enhance repeatedly. These concepts would inform the event of Lean-Agile methodologies within the many years to return.

In the meantime, software program builders started to independently develop new Lean-inspired methodologies and frameworks, together with Scrum, XP, Crystal, and Adaptive Software program Improvement. These typically originated from in-house efforts to enhance effectivity, however builders had additionally begun to share their concepts by publications and displays.

Agile Approaches

In February 2001, a bunch of software program trade leaders met in Snowbird, Utah, to plan an answer for effectivity issues in software program growth. The attendees included a number of folks already credited with launching Lean-inspired methodologies, together with Jim Highsmith (Adaptive Software program Improvement); Jeff Sutherland, Ken Schwaber, and Mike Beedle (Scrum); Kent Beck, Ron Jeffries, and Ward Cunningham (XP); and Alistair Cockburn (Crystal).

The assembly resulted within the Manifesto for Agile Software Development (typically known as the Agile Manifesto), by which the attendees laid out 12 Lean-inspired principles for software program growth. The rules emphasised the significance of adapting to altering necessities and buyer wants, minimizing waste, and delivering working software program quicker utilizing an incremental strategy. The core values of the Agile Manifesto are broadly recognized right now however price reiterating. These values prioritize:

• People and interactions over processes and instruments.
• Working software program over complete documentation.
• Buyer collaboration over contract negotiation.
• Responding to vary over following a plan.

In 2002, Jim Highsmith expounded on Agile rules in Agile Software Development Ecosystems. The e book described the sooner Lean-inspired strategies like Scrum and XP as strategies for attaining Agile software program growth.

Within the years following the Agile Manifesto, further frameworks and methodologies emerged, placing the philosophy’s values and rules into apply. Mary and Tom Poppendieck printed Lean Software Development: An Agile Toolkit in 2003. Their strategy makes use of the seven types of waste in Lean manufacturing as a jumping-off level for Agile software program growth. In 2010, David J. Anderson, a software program engineer at Microsoft, formally outlined Kanban, one other Lean-inspired methodology, in his e book Kanban: Successful Evolutionary Change for Your Technology Business.

Right now, the 2 most distinguished Agile-enabled frameworks are Scrum and Kanban. I talk about these two frameworks within the following sections, exhibiting the similarities and variations between them.

Scrum

Scrum has confirmed to be the most well-liked Agile-enabled framework, utilized by 87% of respondents, based on the 2022 State of Agile Report. (Many individuals used multiple framework or methodology.) The time period “scrum” originates in rugby, the place it describes a good formation of gamers across the ball. It was launched in a producing context by Hirotaka Takeuchi and Ikujiro Nonaka in a 1986 Harvard Business Review article. They used the time period to explain the teamwork required to maneuver a challenge “downfield.”

Scrum entered the software program trade in 1993 when Jeff Sutherland started implementing Scrum processes with colleagues on the Easel Company. Two years later, Sutherland and Ken Schwaber introduced a paper on the Scrum growth course of at a software program trade convention. Schwaber then labored with Mike Beedle to element the strategy of their 2002 e book Agile Software Development with Scrum. In that very same 12 months, the Scrum Alliance was shaped by Schwaber, together with Mike Cohn and Esther Derby; since then, it has grown to turn into the world’s largest Agile and Scrum certification {and professional} networking group.

Scrum Overview

Scrum is an incremental and iterative framework for software program growth. Its rules and practices assist groups work briefly cycles, enabling speedy response to suggestions and altering wants. The framework is prescriptive, with clearly outlined workforce constructions, workflows, occasions, and phrases.

Scrum entails self-organizing, self-managing teams of often 5 to seven workforce members. One member is called the Scrum grasp: This servant-leader facilitates collaboration and enforces Scrum processes, however will not be chargeable for assigning duties or product supply. One other member, the product proprietor, defines the imaginative and prescient for the workforce, engages with different stakeholders, and finally accepts or rejects the workforce’s work. Groups are cross-functional; members work collectively and will not be sure to distinct roles like architect, programmer, designer, or tester.

Work happens briefly, time-boxed iterations known as sprints, usually one to 4 weeks in period. The dash focuses on work objects from a prioritized “product backlog” established earlier than the dash begins. The workforce goals to ship working software program on the finish of every dash, enabling speedy suggestions cycles.

Scrum Course of

Earlier than a dash can start, the product proprietor creates a product backlog. The backlog often begins with growth objects known as “person tales.” The tales outline product options from an end-user perspective. Analysis and prototyping duties are known as “spikes” and are generally required earlier than the workforce can start a narrative. The product proprietor arranges the backlogged work in precedence order.

As soon as a product backlog is created and prioritized, the continued backlog refinement course of takes over. The Scrum workforce evaluations an inventory of tales and different duties. They meet with the product proprietor and Scrum grasp and talk about “acceptance standards” for every story (i.e., the testable necessities specified by the product proprietor). In addition they consider complexity, threat, measurement, implementation technique, and different components. As soon as the individuals set up a standard understanding of every story, they estimate the trouble required to finish the duty by evaluating it to a earlier, well-understood piece of labor and assigning size-based values known as “story factors.”

To formally launch the dash, the Scrum grasp facilitates a dash planning assembly with the Scrum workforce and the product proprietor. The workforce determines its dash capability, which is the variety of story factors it might probably deal with based mostly on the out there time and sources. The product proprietor presents objects from the product backlog, and the workforce discusses every story and breaks down the subtasks required for the story to satisfy the “definition of done” (DoD). They proceed pulling tales from the backlog till reaching the dash capability. The tales are organized on a table-style show known as a Scrum board, the place the workforce will monitor progress through the dash. After reviewing the dash scope, the Scrum workforce (however not the Scrum grasp or product proprietor) commits to finishing the work (i.e., the “dash backlog”), and the dash commences.

Firstly of every day through the dash, the Scrum grasp facilitates a quick, 15-minute assembly with the Scrum workforce and product proprietor to plan and evaluate progress. This quick assembly is called the “each day scrum.” Every particular person briefly studies on work executed the day earlier than, the work deliberate for the present day, and any impediments. When a workforce member identifies an impediment, the Scrum grasp provides the merchandise to an “impediments backlog,” offering visibility for the workforce. The Scrum grasp is chargeable for addressing points on the impediments backlog.

Along with sustaining the Scrum board, the Scrum grasp displays progress with a burndown chart. The chart exhibits the quantity of labor accomplished, measured in story factors. The remaining story factors are proven on the Y axis, and the remaining time is proven on the X axis. The Scrum grasp updates the dash burndown chart because the workforce completes tales.

On the finish of the dash, the Scrum grasp facilitates a dash demo assembly at which the workforce presents every accomplished story utilizing the working software program. The product proprietor will approve the story if all of the acceptance standards are met. If a narrative is rejected, the product proprietor identifies the shortfalls, and the story returns to the product backlog in its precedence order. Usually, the rejected portion of a narrative is transformed right into a separate story, and the unique is closed.

After the dash demo, the Scrum grasp facilitates a closing assembly generally known as the dash retrospective. The workforce displays on the dash and evaluates what went nicely and what didn’t. This course of generates an inventory of enchancment motion objects, which can be added to the product backlog or trigger adjustments to the workforce constitution.

Benefits and Disadvantages of Scrum

As a result of Scrum groups prioritize backlog objects and work briefly iterations that all the time produce working software program, Scrum permits clients to find out what they like (and don’t like) and request adjustments throughout product growth. The overhead prices for course of and administration are decrease, resulting in faster, cheaper outcomes.

Nonetheless, Scrum will not be one of the best challenge administration course of in some conditions. Organizations ought to perceive points that may come up from this framework:

• Transparency: Scrum will increase transparency and accountability. Though transparency is advantageous, it may be uncomfortable when issues and poor efficiency are uncovered, resulting in resistance if not appropriately dealt with throughout the Scrum framework of steady enchancment.
• Workforce expertise and dedication: Inexperienced or uncommitted Scrum groups or Scrum masters may cause critical issues by misapplying the Scrum framework. As a result of workforce members shouldn’t have outlined roles, all members should possess related technical expertise. Scrum additionally advantages from dedication coming from different components of the group.
• Scope creep: One of many important benefits of Scrum is that groups and stakeholders can alter priorities and scope alongside the way in which, however this may also be an obstacle if self-discipline isn’t used. Scope creep is a particular concern for tasks with no outlined finish date, as stakeholders could proceed including work objects.
• Poorly outlined work: Poorly outlined and understood person tales or duties can result in rework, inaccurate estimates, and scope creep. Though Scrum prioritizes creating working software program over documentation, the product proprietor should clearly talk standards and expectations.
• Scaling: Scrum capabilities greatest with smaller groups. Giant groups require a distinct strategy.

Scrum is a superb framework for tasks with necessities which are unsure or anticipated to vary. It’s best-suited for skilled, motivated groups, because it empowers them to arrange their work and consider progress and issues. Scrum groups typically enhance and turn into extra productive over time.

Kanban

Kanban is an Agile administration course of that focuses on visualization, workflow, and limiting work in progress. The idea emerged straight from the TPS, by which the time period kanban (or “signboard”) refers to tags on merchandise and supplies. When a Toyota employee removes the kanban and sends it down the manufacturing line, a brand new order is initiated.

Software program builders started to undertake Kanban following David J. Anderson’s 2010 e book Kanban: Profitable Evolutionary Change for Your Expertise Enterprise, which outlined strategies used at Microsoft. In recent times, its use has expanded quickly. The 2022 State of Agile Report discovered that 56% of Agile groups use Kanban, making it the second-most standard methodology following Scrum.

Kanban Course of

In software program growth, Kanban resembles a light-weight and fewer regimented model of Scrum. The workforce makes use of a Kanban board to visualise work in progress. The board is just like a Scrum board, however the workflow doesn’t advance in time-boxed sprints. As a substitute, Kanban permits for a continuing circulation of labor however limits what number of objects occupy every standing at one time based mostly on workforce capability. The workforce can’t pull new work till present work advances.

As a result of Kanban groups will not be required to work in sprints, the groups don’t comply with a prescribed course of conferences for planning, product demonstrations, retrospectives, and so forth. Steady enchancment is completed by monitoring and analyzing the circulation of things and making incremental enhancements as points are uncovered.

Kanban doesn’t prescribe particular roles for workforce members, though a challenge supervisor typically facilitates actions and ensures that work objects are prioritized and clearly understood. A single Kanban board may even be shared throughout groups.

This desk is an outline comparability of Kanban and Scrum:

General, Kanban is a extremely adaptable methodology that’s well-suited for groups making incremental enhancements to a product. It requires much less coaching than Scrum and is extra versatile. Kanban will be mixed with different frameworks and may even be implemented at enterprise scale.

Past the Blueprint

In keeping with the Standish Group, tasks that implement Agile frameworks and methodologies are roughly four times more likely to succeed than these utilizing extra conventional strategies. The most well-liked Agile-inspired project-managed blueprints used for software program growth have their historic roots in Lean manufacturing and TPS and have remodeled the software program trade over the previous three many years.

A superb understanding of Lean, Agile, Scrum, and Kanban is prime to the sphere of challenge administration and having all of them defined in a single place permits additional steady enchancment and development as groups and firms scale utilizing Waterfall, DAD, SAFe, and different hybrid approaches.

This text has lately undergone a complete replace to include the newest and most correct data. Feedback beneath could predate these adjustments.