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 improvement. Whereas they share a lineage, every provides a distinct strategy to managing software program improvement tasks—and every has distinct benefits and limitations.

On this challenge administration blueprint, I focus on 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 business right now.

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 (identified in Japanese as muda) arises on account 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 forestall 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 pace or product completion instances. It will increase the danger of overburden, creating waste. Coaching employees on a number of machines for elevated flexibility and forecasting demand may also help scale back unevenness.

To take away these impediments, Toyota established its manufacturing system on a core idea often 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 often known 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 mechanically when an issue occurred. The corporate additionally empowered employees to cease manufacturing after they observed irregularities.

TPS emphasizes the need of steady enchancment, on-the-ground statement, and respect for individuals via 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 coming into software program improvement 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 tasks had been an unqualified success. These deficiencies had been partly on account of conventional Waterfall methodologies, which outlined necessities initially of multiyear tasks and resulted in late or over-budget software program supply. In some circumstances, the deliverables had been out of date on account of market modifications that had occurred throughout a challenge.

Early enhancements to Waterfall included speedy software improvement, which emerged at IBM and unfold with the publication of James Martin’s 1991 ebook Speedy Software Growth. This technique targeted on waste discount through methods similar to speedy prototyping. Software program builders additionally moved towards incremental improvement, including options in a continuous iteration of small tasks. Whereas these methods of working helped, they didn’t remedy the core issues related to Waterfall.

One other vital improvement occurred inside 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 constantly. 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 Growth. These typically originated from in-house efforts to enhance effectivity, however builders had additionally begun to share their concepts via publications and displays.

Agile Approaches

In February 2001, a gaggle of software program business leaders met in Snowbird, Utah, to plot an answer for effectivity issues in software program improvement. 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 (typically known as the Agile Manifesto), during which the attendees laid out 12 Lean-inspired ideas for software program improvement. The ideas 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 identified 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 ideas in Agile Software program Growth Ecosystems. The ebook described the sooner Lean-inspired strategies like Scrum and XP as methods for reaching Agile software program improvement.

Within the years following the Agile Manifesto, extra frameworks and methodologies emerged, placing the philosophy’s values and ideas into apply. Mary and Tom Poppendieck revealed Lean Software program Growth: 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 improvement. 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 present, the 2 most outstanding Agile-enabled frameworks are Scrum and Kanban. I focus on these two frameworks within the following sections, exhibiting the similarities and variations between them.

Scrum

Scrum has confirmed to be the preferred Agile-enabled framework, utilized by 87% of respondents, in response to 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 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 Evaluation article. They used the time period to explain the teamwork required to maneuver a challenge “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 offered a paper on the Scrum improvement 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 yr, the Scrum Alliance was shaped 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 improvement. Its ideas 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 includes 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 just isn’t answerable 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 usually are not 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 length. 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 improvement objects 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 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 continuing backlog refinement course of takes over. The Scrum workforce critiques 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, danger, dimension, implementation technique, and different components. As soon as the individuals set up a typical 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 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 meet the “definition of completed” (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 observe progress in the course of 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.

At the start of every day in the course of the dash, the Scrum grasp facilitates a quick, 15-minute assembly with the Scrum workforce and product proprietor to plan and evaluation progress. This quick assembly is called the “each day scrum.” Every particular person briefly experiences on work completed 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 answerable 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 last assembly often known as the dash retrospective. The workforce displays on the dash and evaluates what went effectively and what didn’t. This course of generates a listing of enchancment motion objects, which can be added to the product backlog or trigger modifications 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 prospects to find out what they like (and don’t like) and request modifications throughout product improvement. The overhead prices for course of and administration are decrease, resulting in faster, cheaper outcomes.

Nonetheless, Scrum just isn’t the very 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 inside the Scrum framework of steady enchancment.
• Group expertise and dedication: Inexperienced or uncommitted Scrum groups or Scrum masters may cause severe issues by misapplying the Scrum framework. As a result of workforce members wouldn’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 principal benefits of Scrum is that groups and stakeholders can alter priorities and scope alongside the way in which, however this may also be a drawback if self-discipline isn’t used. Scope creep is a particular concern for tasks and not using a outlined finish date, as stakeholders could proceed including work objects.
• Poorly outlined work: Poorly outlined and understood consumer 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 features finest with smaller groups. Massive groups require a completely different strategy.

Scrum is a superb framework for tasks with necessities which can be 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 typically 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 instantly from the TPS, during 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 methods used at Microsoft. Lately, 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 improvement, 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 continuous circulate 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 usually are not required to work in sprints, the groups don’t observe 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 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:

Total, 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 could be mixed with different frameworks and might even be carried out at enterprise scale.

Past the Blueprint

In response to the Standish Group, tasks that implement Agile frameworks and methodologies are roughly 4 instances extra prone to succeed than these utilizing extra conventional strategies. The most well-liked Agile-inspired project-managed blueprints used for software program improvement have their historic roots in Lean manufacturing and TPS and have reworked the software program business over the previous three many years.

An excellent understanding of Lean, Agile, Scrum, and Kanban is key to the sector 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 just lately undergone a complete replace to include the newest and most correct info. Feedback beneath could predate these modifications.