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 gives a unique method to managing software program growth initiatives—and every has distinct benefits and limitations.

On this venture administration blueprint, I focus on the Lean and Agile philosophies and hint their discursive evolution and utilized follow 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 business as we speak.

Lean Philosophies

The time period “Lean” advanced from the Toyota Manufacturing System (TPS), a producing mannequin developed by Sakichi Toyoda, Kiichiro Toyoda, and Taiichi Ohno. The system revolutionized manufacturing from the 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 as a result of defects, overproduction, ready, transport, inventories, movement, and extra processing. (Many corporations now acknowledge unused expertise as an eighth kind of waste.)

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

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

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

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

TPS emphasizes the need of steady enchancment, on-the-ground remark, and respect for individuals by means of teamwork and collaboration. Toyota’s philosophy and practices had been additional popularized within the 1990 ebook The Machine That Modified the World by James P. Womack, Daniel T. Jones, and Daniel Roos, which cited TPS because the mannequin for “Lean manufacturing.”

Lean Developments

Lean ideas started getting into software program growth within the Nineteen Nineties. At that time, the business was in determined want of recent approaches. A 1994 report by the Standish Group discovered that fewer than one in 5 software program initiatives had been an unqualified success. These deficiencies had been partly as a result of conventional Waterfall methodologies, which outlined necessities initially of multiyear initiatives and resulted in late or over-budget software program supply. In some circumstances, the deliverables had been out of date as a result of market modifications that had occurred throughout a venture.

Early enhancements to Waterfall included fast software growth, which emerged at IBM and unfold with the publication of James Martin’s 1991 ebook Speedy Software Growth. This technique centered on waste discount by way of strategies similar to fast prototyping. Software program builders additionally moved towards incremental growth, including options in a continuing iteration of small initiatives. 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 Pondering. The ebook outlined the ideas of Lean administration, distilling the core Lean values of steady enchancment and respect for individuals into 5 prescriptive ideas that could possibly be used to eradicate waste and enhance repeatedly. These concepts would inform the event of Lean-Agile methodologies within the many years to come back.

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 Growth. These usually originated from in-house efforts to enhance effectivity, however builders had additionally begun to share their concepts by means of publications and displays.

Agile Approaches

In February 2001, a bunch of software program business leaders met in Snowbird, Utah, to plot an answer for effectivity issues in software program growth. The attendees included a number of individuals already credited with launching Lean-inspired methodologies, together with Jim Highsmith (Adaptive Software program Growth); 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 program Growth (usually known as the Agile Manifesto), through which the attendees laid out 12 Lean-inspired ideas for software program growth. The ideas emphasised the significance of adapting to altering necessities and buyer wants, minimizing waste, and delivering working software program sooner utilizing an incremental method. The core values of the Agile Manifesto are extensively recognized as we speak 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 ideas in Agile Software program Growth Ecosystems. The ebook 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 ideas into follow. Mary and Tom Poppendieck revealed Lean Software program Growth: An Agile Toolkit in 2003. Their method 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 ebook Kanban: Profitable Evolutionary Change for Your Know-how Enterprise.

At the moment, the 2 most distinguished Agile-enabled frameworks are Scrum and Kanban. I focus on these two frameworks within the following sections, displaying the similarities and variations between them.

Scrum

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

Scrum entered the software program business 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 business convention. Schwaber then labored with Mike Beedle to element the strategy of their 2002 ebook Agile Software program Growth with Scrum. In that very same 12 months, the Scrum Alliance was fashioned by Schwaber, together with Mike Cohn and Esther Derby; since then, it has grown to grow to be 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 ideas and practices assist groups work in brief cycles, enabling fast response to suggestions and altering wants. The framework is prescriptive, with clearly outlined crew buildings, workflows, occasions, and phrases.

Scrum entails self-organizing, self-managing teams of normally 5 to seven crew members. One member is named 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 crew, engages with different stakeholders, and in the end accepts or rejects the crew’s work. Groups are cross-functional; members work collectively and are usually not sure to distinct roles like architect, programmer, designer, or tester.

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

Scrum Course of

Earlier than a dash can start, the product proprietor creates a product backlog. The backlog normally begins with growth gadgets known as “consumer 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 crew 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 crew evaluations a listing of tales and different duties. They meet with the product proprietor and Scrum grasp and focus on “acceptance standards” for every story (i.e., the testable necessities specified by the product proprietor). Additionally they consider complexity, threat, measurement, implementation technique, and different elements. As soon as the members set up a typical understanding of every story, they estimate the hassle 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 crew and the product proprietor. The crew determines its dash capability, which is the variety of story factors it could possibly deal with primarily based on the obtainable time and assets. The product proprietor presents gadgets from the product backlog, and the crew discusses every story and breaks down the subtasks required for the story to meet the “definition of executed” (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 crew will observe progress through the dash. After reviewing the dash scope, the Scrum crew (however not the Scrum grasp or product proprietor) commits to finishing the work (i.e., the “dash backlog”), and the dash commences.

In the beginning of every day through the dash, the Scrum grasp facilitates a short, 15-minute assembly with the Scrum crew and product proprietor to plan and assessment progress. This brief assembly is named the “day by day scrum.” Every individual briefly studies on work executed the day earlier than, the work deliberate for the present day, and any impediments. When a crew member identifies an impediment, the Scrum grasp provides the merchandise to an “impediments backlog,” offering visibility for the crew. The Scrum grasp is chargeable for addressing points on the impediments backlog.

Along with sustaining the Scrum board, the Scrum grasp screens 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 crew completes tales.

On the finish of the dash, the Scrum grasp facilitates a dash demo assembly at which the crew 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. Typically, 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 remaining assembly referred to as the dash retrospective. The crew displays on the dash and evaluates what went nicely and what didn’t. This course of generates a listing of enchancment motion gadgets, which can be added to the product backlog or trigger modifications to the crew constitution.

Benefits and Disadvantages of Scrum

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

Nevertheless, Scrum will not be the most effective venture 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.
• Crew expertise and dedication: Inexperienced or uncommitted Scrum groups or Scrum masters may cause severe issues by misapplying the Scrum framework. As a result of crew members don’t have outlined roles, all members should possess related technical expertise. Scrum additionally advantages from dedication coming from different elements of the group.
• Scope creep: One of many predominant benefits of Scrum is that groups and stakeholders can alter priorities and scope alongside the best way, however this may also be an obstacle if self-discipline isn’t used. Scope creep is a particular concern for initiatives and not using a outlined finish date, as stakeholders could proceed including work gadgets.
• Poorly outlined work: Poorly outlined and understood consumer tales or duties can result in rework, inaccurate estimates, and scope creep. Though Scrum prioritizes growing working software program over documentation, the product proprietor should clearly talk standards and expectations.
• Scaling: Scrum capabilities finest with smaller groups. Giant groups require a completely different method.

Scrum is a superb framework for initiatives with necessities which are unsure or anticipated to vary. It’s best-suited for knowledgeable, motivated groups, because it empowers them to prepare their work and consider progress and issues. Scrum groups usually enhance and grow to be 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 immediately from the TPS, through 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 ebook Kanban: Profitable Evolutionary Change for Your Know-how 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 common methodology following Scrum.

Kanban Course of

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

As a result of Kanban groups are usually not 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 circulate of things and making incremental enhancements as points are uncovered.

Kanban doesn’t prescribe particular roles for crew members, though a venture supervisor usually facilitates actions and ensures that work gadgets 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 may be mixed with different frameworks and may even be carried out at enterprise scale.

Past the Blueprint

In keeping with the Standish Group, initiatives that implement Agile frameworks and methodologies are roughly 4 instances extra 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 reworked the software program business over the previous three many years.

A very good understanding of Lean, Agile, Scrum, and Kanban is key to the sphere of venture administration and having all of them defined in a single place permits additional steady enchancment and progress as groups and corporations scale utilizing Waterfall, DAD, SAFe, and different hybrid approaches.

This text has not too long ago undergone a complete replace to include the most recent and most correct data. Feedback under could predate these modifications.