Purpose
9.9.1
Document analysis is a means to elicit requirements by studying available documentation on existing and comparable solutions and identifying relevant information.
Description
9.9.2
Document analysis may include analysis of business plans, market studies, contracts, requests for proposal, statements of work, memos, existing guidelines, procedures, training guides, competing product literature, published comparative product reviews, problem reports, customer suggestion logs, and existing system specifications, among others. Identifying and consulting all likely sources of requirements will result in improved requirements coverage, assuming the documentation is up to date.
Document analysis is used if the objective is to gather details of existing solutions, including business rules, entities, and attributes that need to be included in a new solution or need to be updated for the current solution. This technique also applies in situations where the subject matter experts for the existing solutions are no longer with the organization, or are not going to be available throughout the duration of the elicitation process.
Elements
9.9.3
Preparation .1
Evaluate which existing system and business documentation is relevant, available and appropriate for study.
Document Review .2
Study the material and identify relevant business details. ▶
Document business details as well as questions for follow-up with subject matter ▶
experts. Wrap-up .3
Review and confirm the selected details with subject matter experts. ▶
Organize information into requirements format. ▶
Obtain answers to follow-up questions. ▶
Usage Considerations
9.9.4
Advantages .1
Not starting from a blank page. ▶
Leveraging existing materials to discover and/or confirm requirements. ▶
A means to cross-check requirements from other elicitation techniques such as ▶
interviews, job shadowing, surveys or focus groups. Disadvantages
.2
Limited to “as-is” perspective. ▶
Existing documentation may not be up-to-date or valid. ▶
Can be a time-consuming and even tedious process to locate the relevant ▶ information.
Estimation
9.10
Purpose
9.10.1
Estimating techniques forecast the cost and effort involved in pursuing a course of action.
Description
9.10.2
Estimation techniques are used to develop a better understanding of the possible range of costs and effort associated with any initiative. Estimation is used when it is impossible to determine exact costs. Estimation cannot and does not eliminate uncertainty; rather, the purpose of estimation is to get a reasonable assessment of likely costs or effort required.
The less information that is available to the estimator, the greater the range of uncertainty will be. Estimates should be revisited as more information becomes available. Many estimation techniques rely on historic performance records from the organization to calibrate them against actual performance. Estimates should include an assessment of the range of uncertainty associated with that estimate.
Elements
9.10.3
Analogous Estimation .1
Use of a similar project as the basis for developing estimates for the current project. It is used when little is known. Analogous estimating is often used to develop a rough order of magnitude (ROM) estimate, and is also known as “top-down” estimating. This is usually done at the beginning of the project or project phase and more detailed estimates follow as more is known.
Parametric Estimation .2
The use of parameters, multiplied by the number of hours. For parametric estimating to be usable, enough history has to be available to be used as a basis of comparison. With this type of estimating, the business analyst has done enough work to determine which parameters can be used and how many there will be. For example, the business analyst has determined that there will be ten use cases developed. The business analyst also has history that indicates for each use case the total hours that will be spent, in this case will be 20 hours. Using this technique, the business analyst can multiply 10 x 20 to get a total, or 200 hours.
Techniques Estimation
development, such as COCOMO II, Function Point Counting, Use Case Points, and Story Points.
Bottom-up Estimation .3
Using this technique the business analyst has collected the deliverables, activities, tasks, and estimates from all the involved stakeholders and rolls them up to get a total for all the activities and tasks. Because it is normally easier to estimate smaller items than larger items, bottom-up estimating can produce the most accurate and defensible estimates.
Rolling Wave .4
This is a technique involving refinement of estimates. Estimate the details for activities in the current iteration or increment and provide an analogous estimate for the entire scope of work. As the end of the iteration approaches, estimates for the next iteration can be made and the initial estimate for all activities is refined.
Three-point Estimation .5
Uses scenarios for:
The most optimistic estimate, or best-case scenario ▶
The most pessimistic estimate, or worst-case scenario ▶
The most likely estimate ▶
Note that the most likely estimate is not an average of best and worst case scenarios. It requires in depth knowledge of the situation. Under the right circumstances, the best- case scenario may also be the most likely.
Historic Analysis .6
Uses history as a basis for estimating. It is similar to analogous estimation, but is used not only for the top-down estimate, but for the detailed tasks as well. Historic estimates require prior project records, whether maintained formally in a project repository or informally in individual project documentation.
Expert Judgment .7
Estimating relies on the expertise of those who have performed the work in the past. These experts can be internal or external to the project team or to the organization.
Delphi Estimation .8
This technique uses a combination of expert judgment and history. There are several variations on this process, but they all include individual estimates, sharing the estimates with experts, and having several rounds until consensus is reached. An average of the three estimates is used. Sometimes the average is weighted by taking the optimistic, pessimistic and four times the most likely, dividing by six to get the average.