Eight Steps to Crafting a Business Rule (Part 1)
In this series of articles, I will describe eight steps to crafting a business rule. I use the term 'crafting' intentionally because I believe that writing an accurate, complete, and comprehensible business rule is more art than science. It takes a certain skill, discipline, and (dare I say) craftsmanship.
However, I also believe that there are certain techniques you can use to help you achieve the goal of writing business rules in a consistent fashion.
This eight-step approach arose out of training that I developed for a client based on the RuleSpeak® technique developed by Ron Ross and Gladys Lam (who are both very familiar to readers of these pages). It originally started out as six steps, but then Gladys and Ron did their magic with it and — presto chango! — it became eight steps.
The approach is intended as a practical guide that any Business Analyst (BA) can use when tasked with writing business rules.
The eight steps are:
- Extract the business rule.
- Determine whether the business rule already exists.
- Determine whether the business rule computes or derives something.
- Start with the subject.
- Choose the form of the business rule keyword.
- Say something about the subject.
- Add the condition(s).
- Make sure the business rules all fit together.
This month's article will focus on Step 1.
Step 1: Extract the Business Rule.
There are numerous sources for a business rule, so the first decision is to determine what is the best (sometimes called "trusted") source for the set of business rules within your scope.
The most common sources are:
- Subject Matter Experts (SMEs).
- Documents (both business and technical).
Source: Subject Matter Experts
If you are dealing with SMEs, whether in an interview or a facilitated session, the important thing is to know what questions to ask to elicit the information you need. You don't need to know the ins and outs of the business area — that's the SME's job. You just need to provide the structure and techniques to drive out the business rules.
As there is already lots of material on interviewing and facilitation techniques, I won't go into that here. Just make sure you have the right people in the room, are fully prepared, and know what you want to get out of each session.
The outcome of the interview or facilitated session should be a set of business rules in draft form. Sometimes it is possible to be very close to the final form of the business rule, but, more often, you come out of the session with a very rough draft.
Whether you're dealing with business or technical documents, it is important to understand two things:
- The purpose of the document.
- The intended audience.
Documents always have a specific purpose. The purpose drives the way the document is structured as well as the vocabulary used in the document. For example, a document describing a product or service that is handed out to customers might follow the way a customer would ask questions about the topic. The document might also use very basic language rather than industry-speak.
The intended audience has an impact on the perspective and tone of the document. For example, a customer-facing website might use "you" as the perspective to make the customer feel comfortable. It would likely be written in a very friendly tone. Legislation, however, tends to be targeted to a broad audience and is often formal in tone.
Understanding the purpose and intended audience of your source documents will help to identify what you need to focus on and what you can ignore.
Once you understand the purpose and audience, read the document (or relevant sections) from end-to-end without thinking about the rules. If, after the first read-through, you're totally confused and have no idea how you're going to extract the rules, don't panic! It happens to me all the time. Re-read the document a few more times to get comfortable with the language, the structure, and what it's trying to say.
Now you're ready to roll up your sleeves and extract the rules:
- Using a pencil or highlighter, go through the document and highlight the business terms (aka nouns) that keep cropping up in the document.
- Look for rule-ish words that indicate some kind of constraint, restriction, or limitation such as 'must', 'should', 'will', 'have to', 'shall', 'only' or 'may'. Also look for statements that must be true or false.
- Look for words that might indicate a computation. This includes words like 'total', 'sum', 'add', 'subtract', 'multiply', 'divide', 'is calculated as', and any kind of number.
- Look for anything that indicates a derivation. This usually involves giving something a special name or qualifying it in some way (e.g., "overdue invoice") and providing conditions for determining whether it is true or false (e.g., "An overdue invoice is an invoice that hasn't been paid more 30 days from the invoice date.").
As you go through the document, always keep scope in mind. There is often a lot of "fluff" or irrelevant information that you can ignore. Understanding your scope helps you focus on the important parts.
A few times in my career, I have been asked to extract business rules from program code. It's very difficult to do and doesn't always produce the desired results. If you're in that situation, make sure to team up with a developer who can guide you through the code. And try not to get bogged down in the system rules — look for true business rules.
Now that you are comfortable with the source material, you are ready to systematically go through the next six steps with each potential business rule you've highlighted. The last step involves checking that the whole set of rules works together.
Next month, I'll talk about Step 2 — determining whether the business rule already exists.
Ronald G. Ross with Gladys S.W. Lam, Building Business Solutions: Business Analysis with Business Rules, An IIBA® Sponsored Handbook. Business Rule Solutions, LLC (October 2011), 304 pp. URL: http://www.brsolutions.com/bbs
Gladys S. W. Lam, "Family Reunion... Facilitated Session… Having the Right People Doing the Right Things," Business Rules Journal, Vol. 5, No. 6 (June 2004), URL: http://www.BRCommunity.com/a2004/b194.html
For more information on the RuleSpeak® technique, visit http://www.rulespeak.com
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