Defining Requirement Types: Traditional vs. Use Cases vs. User Stories

[article]

I’ve worked with a lot of teams transitioning to agile. In each situation, user stories always seem to be a sticking point, with a common question being, “What are the differences between traditional requirements, use cases, and user stories?” I’d like to answer this question with a description and example of each requirement type. I’ll also use a running example: Imagine that we’re writing software for placement firms, and one of the firms has requested the ability to search for candidates for a specific role by specialty within a geographic location. For example, “I want to find all business analysts who are Sarbanes Oxley (SOX) experts within fifty miles of New York City.”

ChoiceTraditional Requirements
Traditional requirements are usually thought of as capabilities and constraints of the system; the key term being system. All good requirements describe what the system can do or shouldn’t do, but those requirements that focus intensely on the system tend to deemphasize user interaction or business context related to the user or business. To be fair, many traditional requirements do provide context for business and users, but that is usually not the main focus of the requirement, rather it’s the system that is the focus.

The difficulty with having the system be the focus is that it’s easy to make assumptions about what the user wants.  I’ve seen requirements be the source of record for the system’s operation.  In such a case, interacting with the business or the user while the system is being developed reverted to a series of painful, negotiated change request. The work became a matter of giving the user exactly what she asked for, which may not at all be what she needed.

This is what really makes traditional requirements tough: They’re written from the system perspective. Additionally, they’re often written in the context of a process that enforces change control and a contract based on the requirements themselves. Throw in an ideology that encourages written communication between the business analyst and the development team, and you’ve got a tough job ahead when it comes to delivering value.  Changes become a series of tightly controlled negotiations.

According to the International Institute of Business Analysts (IIBA), good requirements can be described via these criteria:

  • Requirements are complete. They must be as complete as possible with no open-ended parts or opportunity for interpretation.
  • Requirements are testable. One must be able to create a test or some sort of proof that the requirement has been met.
  • Requirements must be consistent with each other with no conflicts between what they are specifying.
  • Requirements must be design-free. Software requirements should be specified in what the system must or must not do, but not in how the software will ensure the requirement is met; that’s design.
  • Requirements must be unambiguous. No wishy-washy statements nor (conceptually) anything that can be interpreted differently than intended.

As you can imagine, good traditional requirements are tough to write and are a rare commodity. If creating a good requirement is tough, writing an entire body of requirements into a complete and locked-down specification of the system is even tougher. The level of detail can lead to many interdependencies between requirements that have to be analyzed as the requirements are developed. While all requirements specifications have this difficulty, traditional requirements are particularly touchy since the focus is on the system rather than any user interaction.

The user understandably concentrates on the interface and his interaction with the system. A simple change in the user interface can create a ripple effect through the requirements. Unless a good requirements trace is available, even small

User Comments

25 comments
Anonymous's picture
Anonymous

Hi Charles,
A short reaction on your great post from a requirements specialist in The Netherlands.
I agree mostly with you, traditional requirements are to much system focussed while requirements should, in my opinion, be user focussed. And both use cases and user stories are user focussed. And it is also true that user cases focus on value. A problem with user stories I've seen in practice is that user stories can be fragmented, users only see a small part of the big picture and sometime users miss the overview. In these situations story boards don't do the job all the time. Because use cases are more narritive users can better see the cohesion, the big picture.
In my experience you can use both use cases and user stories in an agile project. Which of the two depends on the situation, I agree on this point with you.
Great post, it made me think and cleared my opinion on this point.
Keep up the great work!

Jan Jaap Cannegieter

January 26, 2012 - 2:42am
Anonymous's picture
Anonymous

Hi Charles,
A short reaction on your great post from a requirements specialist in The Netherlands.
I agree mostly with you, traditional requirements are to much system focussed while requirements should, in my opinion, be user focussed. And both use cases and user stories are user focussed. And it is also true that user cases focus on value. A problem with user stories I've seen in practice is that user stories can be fragmented, users only see a small part of the big picture and sometime users miss the overview. In these situations story boards don't do the job all the time. Because use cases are more narritive users can better see the cohesion, the big picture.
In my experience you can use both use cases and user stories in an agile project. Which of the two depends on the situation, I agree on this point with you.
Great post, it made me think and cleared my opinion on this point.
Keep up the great work!

Jan Jaap Cannegieter

January 26, 2012 - 2:42am
Anonymous's picture
Anonymous

This is a interesting synopsis. Thanks for putting forth the examples and addressing this really common question, Dr. Suscheck.

I'm not sure I agree with the characterization of "traditional requirements." Seems to me that if you have a Business Requirements Document (BRD), it provides a business context and decidedly describes the business needs. With that in hand, one can write a Systems Requirements Specification (SRS) designed to meet the needs of the BRD. So, not sure the difference is a "system focus" vs. a "business focus" one.

I do think there are important distinctions.

Traditional requirements...

  1. are monolithic -- they are expressed in single documents which make them hard (not impossible) to separate, prioritize, work on, individually. There's a sense of "all or nothing" in this (you either approve the document or you don't).
  2. demand unavailable foresight -- in that to be "complete" requires people to be precise about things they don't know, either because they really have to "see it to know the difference" or there are interactions that are too complex to workout (or even see) ahead of time.
  3. are relatively massive -- in the physics sense... in that, because they are so detailed, they become a thing to maintain in and of themselves and thus effect an inertia. If they are complete, there is so much detail contained within that only those most intimate to the process actually critically read these documents. Once created and matured, these are often incredible expensive to maintain... and at some point they are abandoned.

Where as User Stories...

  1. are a decomposition into discrete units of work. These can be arranged in a number of ways and with relative ease. They each have their own lifecycle thereby allowing the PO to approve some and hold others.
  2. allow you to write at the level of detail you know now -- by allowing some requirements (either not well understood or not high priority) to be expressed more generally (via epics) and others (better understood or higher priority) to be decomposed into more detail respects the fact that learning is inherent in all but the most trivial knowledge work.
  3. are light-weight -- each story is expressed in the most important terms: what feature is being developed (serving a specific business need). The how can be documented (and should be where there are important details that impact correctness) as needed. In this way, the details are hashed out in the most effective way to align: through face-to-face conversations. Yes, as decisions are made, it can really help to write down the salient points.

All that said, the real value is not in what's written down, but the critical thinking that goes into it. In other words, "it's not the plan, but the planning." So, whether someone is critically thinking by writing, or critical thinking by whiteboarding, dialoging, it's the thinking that's the real value. If someone organizes their thoughts best by writing it out in a document, awesome, let 'em run. However, in terms of how the team executes on that thinking, there are clear benefits to writing requirements as User Stories.

The true value of having requirements articulated from a business perspective, from start to finish, is the alignment of the tooling with the need. At the delivery level, mutual understanding of need is the most critical thing. At the product level, aligning our work along the dimension of value streams (e.g. how does providing this incremental feature support, enhance, or optimize an existing step in a business process).

All other writing down is busywork and therefore waste.

(jesh! that last sentence sounds so final. In reality, I'm open to new data that shows otherwise... perhaps my blind spots are some assumptions I'm making about the context in which User Stories are utilized...)

January 26, 2012 - 7:35pm
Anonymous's picture
Anonymous

This is a interesting synopsis. Thanks for putting forth the examples and addressing this really common question, Dr. Suscheck.

I'm not sure I agree with the characterization of "traditional requirements." Seems to me that if you have a Business Requirements Document (BRD), it provides a business context and decidedly describes the business needs. With that in hand, one can write a Systems Requirements Specification (SRS) designed to meet the needs of the BRD. So, not sure the difference is a "system focus" vs. a "business focus" one.

I do think there are important distinctions.

Traditional requirements...

  1. are monolithic -- they are expressed in single documents which make them hard (not impossible) to separate, prioritize, work on, individually. There's a sense of "all or nothing" in this (you either approve the document or you don't).
  2. demand unavailable foresight -- in that to be "complete" requires people to be precise about things they don't know, either because they really have to "see it to know the difference" or there are interactions that are too complex to workout (or even see) ahead of time.
  3. are relatively massive -- in the physics sense... in that, because they are so detailed, they become a thing to maintain in and of themselves and thus effect an inertia. If they are complete, there is so much detail contained within that only those most intimate to the process actually critically read these documents. Once created and matured, these are often incredible expensive to maintain... and at some point they are abandoned.

Where as User Stories...

  1. are a decomposition into discrete units of work. These can be arranged in a number of ways and with relative ease. They each have their own lifecycle thereby allowing the PO to approve some and hold others.
  2. allow you to write at the level of detail you know now -- by allowing some requirements (either not well understood or not high priority) to be expressed more generally (via epics) and others (better understood or higher priority) to be decomposed into more detail respects the fact that learning is inherent in all but the most trivial knowledge work.
  3. are light-weight -- each story is expressed in the most important terms: what feature is being developed (serving a specific business need). The how can be documented (and should be where there are important details that impact correctness) as needed. In this way, the details are hashed out in the most effective way to align: through face-to-face conversations. Yes, as decisions are made, it can really help to write down the salient points.

All that said, the real value is not in what's written down, but the critical thinking that goes into it. In other words, "it's not the plan, but the planning." So, whether someone is critically thinking by writing, or critical thinking by whiteboarding, dialoging, it's the thinking that's the real value. If someone organizes their thoughts best by writing it out in a document, awesome, let 'em run. However, in terms of how the team executes on that thinking, there are clear benefits to writing requirements as User Stories.

The true value of having requirements articulated from a business perspective, from start to finish, is the alignment of the tooling with the need. At the delivery level, mutual understanding of need is the most critical thing. At the product level, aligning our work along the dimension of value streams (e.g. how does providing this incremental feature support, enhance, or optimize an existing step in a business process).

All other writing down is busywork and therefore waste.

(jesh! that last sentence sounds so final. In reality, I'm open to new data that shows otherwise... perhaps my blind spots are some assumptions I'm making about the context in which User Stories are utilized...)

January 26, 2012 - 7:35pm
Anonymous's picture
Anonymous

This is a interesting synopsis. Thanks for putting forth the examples and addressing this really common question, Dr. Suscheck.

I'm not sure I agree with the characterization of "traditional requirements." Seems to me that if you have a Business Requirements Document (BRD), it provides a business context and decidedly describes the business needs. With that in hand, one can write a Systems Requirements Specification (SRS) designed to meet the needs of the BRD. So, not sure the difference is a "system focus" vs. a "business focus" one.

I do think there are important distinctions.

Traditional requirements...

  1. are monolithic -- they are expressed in single documents which make them hard (not impossible) to separate, prioritize, work on, individually. There's a sense of "all or nothing" in this (you either approve the document or you don't).
  2. demand unavailable foresight -- in that to be "complete" requires people to be precise about things they don't know, either because they really have to "see it to know the difference" or there are interactions that are too complex to workout (or even see) ahead of time.
  3. are relatively massive -- in the physics sense... in that, because they are so detailed, they become a thing to maintain in and of themselves and thus effect an inertia. If they are complete, there is so much detail contained within that only those most intimate to the process actually critically read these documents. Once created and matured, these are often incredible expensive to maintain... and at some point they are abandoned.

Where as User Stories...

  1. are a decomposition into discrete units of work. These can be arranged in a number of ways and with relative ease. They each have their own lifecycle thereby allowing the PO to approve some and hold others.
  2. allow you to write at the level of detail you know now -- by allowing some requirements (either not well understood or not high priority) to be expressed more generally (via epics) and others (better understood or higher priority) to be decomposed into more detail respects the fact that learning is inherent in all but the most trivial knowledge work.
  3. are light-weight -- each story is expressed in the most important terms: what feature is being developed (serving a specific business need). The how can be documented (and should be where there are important details that impact correctness) as needed. In this way, the details are hashed out in the most effective way to align: through face-to-face conversations. Yes, as decisions are made, it can really help to write down the salient points.

All that said, the real value is not in what's written down, but the critical thinking that goes into it. In other words, "it's not the plan, but the planning." So, whether someone is critically thinking by writing, or critical thinking by whiteboarding, dialoging, it's the thinking that's the real value. If someone organizes their thoughts best by writing it out in a document, awesome, let 'em run. However, in terms of how the team executes on that thinking, there are clear benefits to writing requirements as User Stories.

The true value of having requirements articulated from a business perspective, from start to finish, is the alignment of the tooling with the need. At the delivery level, mutual understanding of need is the most critical thing. At the product level, aligning our work along the dimension of value streams (e.g. how does providing this incremental feature support, enhance, or optimize an existing step in a business process).

All other writing down is busywork and therefore waste.

(jesh! that last sentence sounds so final. In reality, I'm open to new data that shows otherwise... perhaps my blind spots are some assumptions I'm making about the context in which User Stories are utilized...)

January 26, 2012 - 7:35pm
Anonymous's picture
Anonymous

This is a interesting synopsis. Thanks for putting forth the examples and addressing this really common question, Dr. Suscheck.

I'm not sure I agree with the characterization of "traditional requirements." Seems to me that if you have a Business Requirements Document (BRD), it provides a business context and decidedly describes the business needs. With that in hand, one can write a Systems Requirements Specification (SRS) designed to meet the needs of the BRD. So, not sure the difference is a "system focus" vs. a "business focus" one.

I do think there are important distinctions.

Traditional requirements...

  1. are monolithic -- they are expressed in single documents which make them hard (not impossible) to separate, prioritize, work on, individually. There's a sense of "all or nothing" in this (you either approve the document or you don't).
  2. demand unavailable foresight -- in that to be "complete" requires people to be precise about things they don't know, either because they really have to "see it to know the difference" or there are interactions that are too complex to workout (or even see) ahead of time.
  3. are relatively massive -- in the physics sense... in that, because they are so detailed, they become a thing to maintain in and of themselves and thus effect an inertia. If they are complete, there is so much detail contained within that only those most intimate to the process actually critically read these documents. Once created and matured, these are often incredible expensive to maintain... and at some point they are abandoned.

Where as User Stories...

  1. are a decomposition into discrete units of work. These can be arranged in a number of ways and with relative ease. They each have their own lifecycle thereby allowing the PO to approve some and hold others.
  2. allow you to write at the level of detail you know now -- by allowing some requirements (either not well understood or not high priority) to be expressed more generally (via epics) and others (better understood or higher priority) to be decomposed into more detail respects the fact that learning is inherent in all but the most trivial knowledge work.
  3. are light-weight -- each story is expressed in the most important terms: what feature is being developed (serving a specific business need). The how can be documented (and should be where there are important details that impact correctness) as needed. In this way, the details are hashed out in the most effective way to align: through face-to-face conversations. Yes, as decisions are made, it can really help to write down the salient points.

All that said, the real value is not in what's written down, but the critical thinking that goes into it. In other words, "it's not the plan, but the planning." So, whether someone is critically thinking by writing, or critical thinking by whiteboarding, dialoging, it's the thinking that's the real value. If someone organizes their thoughts best by writing it out in a document, awesome, let 'em run. However, in terms of how the team executes on that thinking, there are clear benefits to writing requirements as User Stories.

The true value of having requirements articulated from a business perspective, from start to finish, is the alignment of the tooling with the need. At the delivery level, mutual understanding of need is the most critical thing. At the product level, aligning our work along the dimension of value streams (e.g. how does providing this incremental feature support, enhance, or optimize an existing step in a business process).

All other writing down is busywork and therefore waste.

(jesh! that last sentence sounds so final. In reality, I'm open to new data that shows otherwise... perhaps my blind spots are some assumptions I'm making about the context in which User Stories are utilized...)

January 26, 2012 - 7:35pm
Anonymous's picture
Anonymous

Great comments. Some of you are really excellent writers with interesting viewpoints of your own. You should apply this skill to writing an article. It's a good experience and gives back to the community much more than a comment on someone else's article can

January 26, 2012 - 7:45pm
Anonymous's picture
Anonymous

Great comments. Some of you are really excellent writers with interesting viewpoints of your own. You should apply this skill to writing an article. It's a good experience and gives back to the community much more than a comment on someone else's article can

January 26, 2012 - 7:45pm
Anonymous's picture
Anonymous

Great comments. Some of you are really excellent writers with interesting viewpoints of your own. You should apply this skill to writing an article. It's a good experience and gives back to the community much more than a comment on someone else's article can

January 26, 2012 - 7:45pm
Anonymous's picture
Anonymous

Great comments. Some of you are really excellent writers with interesting viewpoints of your own. You should apply this skill to writing an article. It's a good experience and gives back to the community much more than a comment on someone else's article can

January 26, 2012 - 7:45pm

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About the author

Charles Suscheck's picture Charles Suscheck

Dr. Charles Suscheck is a nationally recognized agile leader who specializes in agile software development adoption at the enterprise level. He is one of only 11 trainers worldwide and 3 in the US certified to teach the entire Scrum.org cirriculum.  With over 25 years of professional experience, Dr. Suscheck has held positions of Process Architect, Director of Research, Principle Consultant, Professor, and Professional Trainer at some of the most recognized companies in America. He has spoken at national and international conferences such as Agile 200X, OOPSLA, and ECOOP on topics related to agile project management and is a frequent author in industry and academia. Dr. Suscheck has over 30 publications to his credit.

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