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

Over the previous three a long time, Agile-inspired frameworks corresponding to Scrum, Kanban, Excessive Programming (XP), and Lean-Agile have come to dominate software program improvement. Whereas they share a lineage, every gives a distinct method to managing software program improvement 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 observe 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 Manufacturing 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 (identified in Japanese as muda) arises resulting from defects, overproduction, ready, transport, inventories, movement, and extra processing. (Many corporations now acknowledge unused expertise as an eighth sort 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 result from fluctuating buyer demand or variations in operator pace or product completion occasions. It will increase the chance 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 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 have to be ingrained within the manufacturing course of, requiring each automation and human intelligence—a mix referred to 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 individuals by way of teamwork and collaboration. Toyota’s philosophy and practices had been additional popularized within the 1990 guide 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 rules started getting into software program improvement within the Nineteen Nineties. At that time, the trade 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 resulting from conventional Waterfall methodologies, which outlined necessities in the beginning of multiyear tasks and resulted in late or over-budget software program supply. In some instances, the deliverables had been out of date resulting from market modifications that had occurred throughout a challenge.

Early enhancements to Waterfall included speedy utility improvement, which emerged at IBM and unfold with the publication of James Martin’s 1991 guide Fast Software Growth. This technique targeted on waste discount through strategies corresponding 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 Considering. The guide outlined the rules of Lean administration, distilling the core Lean values of steady enchancment and respect for individuals into 5 prescriptive rules that might be used to remove waste and enhance constantly. These concepts would inform the event of Lean-Agile methodologies within the a long time 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 usually originated from in-house efforts to enhance effectivity, however builders had additionally begun to share their concepts by way of publications and shows.

Agile Approaches

In February 2001, a gaggle of software program trade leaders met in Snowbird, Utah, to plan 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 (usually referred to as the Agile Manifesto), wherein the attendees laid out 12 Lean-inspired rules for software program improvement. The rules 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 broadly identified right now however value reiterating. These values prioritize:

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

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

Within the years following the Agile Manifesto, further frameworks and methodologies emerged, placing the philosophy’s values and rules into observe. 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 improvement. In 2010, David J. Anderson, a software program engineer at Microsoft, formally outlined Kanban, one other Lean-inspired methodology, in his guide Kanban: Profitable Evolutionary Change for Your Expertise Enterprise.

At present, the 2 most outstanding Agile-enabled frameworks are Scrum and Kanban. I talk about these two frameworks within the following sections, displaying the similarities and variations between them.

Scrum

Scrum has confirmed to be the preferred Agile-enabled framework, utilized by 87% of respondents, in accordance with the 2022 State of Agile Report. (Many contributors used a couple of 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 Enterprise Evaluate 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 improvement course of at a software program trade convention. Schwaber then labored with Mike Beedle to element the tactic of their 2002 guide 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 turn out 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 rules and practices assist groups work in brief cycles, enabling speedy response to suggestions and altering wants. The framework is prescriptive, with clearly outlined staff buildings, workflows, occasions, and phrases.

Scrum entails self-organizing, self-managing teams of often 5 to seven staff members. One member is named the Scrum grasp: This servant-leader facilitates collaboration and enforces Scrum processes, however is just not liable for assigning duties or product supply. One other member, the product proprietor, defines the imaginative and prescient for the staff, engages with different stakeholders, and finally accepts or rejects the staff’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 referred to 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 staff 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 gadgets referred to as “person tales.” The tales outline product options from an end-user perspective. Analysis and prototyping duties are referred to as “spikes” and are generally required earlier than the staff 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 staff evaluations a listing 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, danger, measurement, implementation technique, and different elements. As soon as the contributors 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 referred to as “story factors.”

To formally launch the dash, the Scrum grasp facilitates a dash planning assembly with the Scrum staff and the product proprietor. The staff determines its dash capability, which is the variety of story factors it could deal with based mostly on the accessible time and sources. The product proprietor presents gadgets from the product backlog, and the staff 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 referred to as a Scrum board, the place the staff will observe progress throughout the dash. After reviewing the dash scope, the Scrum staff (however not the Scrum grasp or product proprietor) commits to finishing the work (i.e., the “dash backlog”), and the dash commences.

Initially of every day throughout the dash, the Scrum grasp facilitates a quick, 15-minute assembly with the Scrum staff and product proprietor to plan and evaluation progress. This quick assembly is named the “each 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 staff member identifies an impediment, the Scrum grasp provides the merchandise to an “impediments backlog,” offering visibility for the staff. The Scrum grasp is liable for addressing points on the impediments backlog.

Along with sustaining the Scrum board, the Scrum grasp displays progress with a burndown chart. The chart reveals 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 staff completes tales.

On the finish of the dash, the Scrum grasp facilitates a dash demo assembly at which the staff 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 referred to as the dash retrospective. The staff 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 staff constitution.

Benefits and Disadvantages of Scrum

As a result of Scrum groups prioritize backlog gadgets and work in brief iterations that at all times produce working software program, Scrum permits clients 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.

Nevertheless, Scrum is just not the perfect 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.
• Workforce expertise and dedication: Inexperienced or uncommitted Scrum groups or Scrum masters could cause severe issues by misapplying the Scrum framework. As a result of staff members don’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 major benefits of Scrum is that groups and stakeholders can regulate priorities and scope alongside the way in which, however this can 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 gadgets.
• Poorly outlined work: Poorly outlined and understood person 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 features greatest with smaller groups. Giant groups require a totally different method.

Scrum is a wonderful framework for tasks with necessities which are unsure or anticipated to alter. 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 turn out 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, wherein 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 guide Kanban: Profitable Evolutionary Change for Your Expertise Enterprise, which outlined strategies 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 standard methodology following Scrum.

Kanban Course of

In software program improvement, Kanban resembles a light-weight and fewer regimented model of Scrum. The staff 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 an alternative, Kanban permits for a continuous stream of labor however limits what number of gadgets occupy every standing at one time based mostly on staff capability. The staff can’t pull new work till current work advances.

As a result of Kanban groups are usually 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 achieved by monitoring and analyzing the stream of things and making incremental enhancements as points are uncovered.

Kanban doesn’t prescribe particular roles for staff members, though a challenge 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 will be mixed with different frameworks and might even be applied at enterprise scale.

Past the Blueprint

In keeping with the Standish Group, tasks that implement Agile frameworks and methodologies are roughly 4 occasions extra prone to succeed than these utilizing extra conventional strategies. The preferred Agile-inspired project-managed blueprints used for software program improvement have their historic roots in Lean manufacturing and TPS and have remodeled the software program trade over the previous three a long time.

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 allows additional steady enchancment and development as groups and firms scale utilizing Waterfall, DAD, SAFe, and different hybrid approaches.

This text has not too long ago undergone a complete replace to include the newest and most correct info. Feedback beneath could predate these modifications.