[MUSIC] In the last lesson, we discussed what requirements are and the different activities associated with them. We learned that requirements are really just a way for us to get client needs expressed in a way which can be turned into real products. We also learned that these requirements can be elicited and expressed most easily when the development team and the clients collaborate. So now that we've gotten our feet wet, let's wade a little deeper. In order to understand how to get the most out of our requirements, we must understand the different types of requirements that may be needed for a software product. When you think of the term requirement, what comes to mind? Perhaps you envision a list of features which should be included in the final version of the product. Perhaps you envisioned a set of descriptions of how the product should perform in different situations. Or maybe you envisioned the reason why that product should exist in the first place. As it turns out, all of these are valid kinds of requirements. Together, they describe what the product should be like, how it should work, and why it should exist in the first place. Let's talk about these in more detail. The first requirement we mentioned - the “why the product is needed”, is called the business requirement. Business requirements outline the purpose of a software project. They give the product owners a reason to pursue the project in the first place. You might imagine these requirements as being separate form the actual development of a product. These requirements are not just personal or ethical reasons. Like, must be first on the market or must be used by as many users as possible. A business requirement must define product needs that provide tangible and quantifiable business value. An example of a business requirement is, I need this product to appeal to clothing designers in India to raise our revenue by $50,000 per year. That is a business requirement. Business requirements are used by your client when creating business strategies and plans. They’re a way for business analysts to review the ultimate business goals for the product. It should be noted that business requirements may also go by other names. The term business requirement could be used to describe requirements which we'll talk about later in this lesson. For our purposes, business requirements refer to just those requirements which make up the why the product should exist. Sometimes the concept of a business requirement is associated with words like budget, policies or regulations. These are examples of what we call business rules. These rules are more specific than business requirements. Business rules constrain how the product functions. They also specify rules that need to be followed in order for the project to be considered successful, or even appropriate. Here are some examples of business rules. A privacy policy where the business requires data be stored securely and not shared with non essential personnel. A brand uniformity requirement where the products to be developed must be visually consistent with other products owned by the client. A government regulation such as a requirement to maintain user data, and any information regarding its manipulation for a specific period of time according to local or international laws. All of these things are business rules. They outline some of the product restrictions. You can imagine business rules as dictating under what restrictions a software product must be developed. We just talked about two requirements types: business requirements and business rules. Suppose you're forming requirements for an invoicing product that needs to calculate sales tax. Which type of requirement are you creating? A. a business requirement, or B. a business rule. The answer is B, business rule. Collecting sales tax is a legal requirement from government upon corporations making sales, which constrains sales-related products. The best answer is a business rule. A business requirement would be more of description of why you're making the product in the first place.