IT Architecture from A to Z: Theoretical basis. First Edition. Vadim Aldzhanov
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milestones, and final results. Any delays in activities within a critical path lead to increasing duration of further activities. If the project duration reduced, the terms of critical activities should also be reduced. Using the critical path method allows you to compare planned and actual indicators (how the situation should develop and what is actually happening) every day. The method consists of four planning stages:
• Goals and limitations (considering the project in several aspects – duration, quality, etc.);
• Duration of activity;
• Network schedule;
• Gantt chart.
Critical Chain Method (CCM) differs from the critical path method by focusing on the use of project resources, rather than project activities. Potential problems with resources, are resolved via buffers to ensure the timely implementation of projects in compliance with all required safety measures. Critical chain method helps avoid delays in the project, determining the critical path of activities, as well as resource reserves (lead-time) for these activities. Since the charts consider the availability of resources, the project may take longer, but the likelihood of failure to meet key events may be reduced. The basis of critical chain method is the formation of the main critical activities of the project and the retention of the terms of activity, as well as the project’s final completion date. Critical activities of the project are logically linked, taking into account resource and administrative constraints. If project resources are not limited, the estimated indicators will be similar to PERT. If the project still has limited resources, it is necessary to:
• determine near-critical work in the schedule, such work very often runs parallel to the main “red” chain, but being reduced, they may easily become critical if they are ignored.
• define a critical project chain using resource links.
Monte Carlo Analysis is a method that recalculates (or iterates) of a project cost or project duration using input values randomly taken from possible values of cost or duration in order to obtain the distribution of value likelihood of the total project cost or project completion dates.
Value Engineering (VE) is a creative approach to optimizing cost at the stages of the project life cycle, reducing time costs, increasing profits, improving quality, expanding the market, solving problems and / or improving the efficiency of resource use.
Earned Value Technique (EVT) (also named as earning rules and crediting method) is a special method for measuring work performance for an element of a hierarchical work structure, a control account or a project.
Bottom-up Estimating is a work element estimating method. Activity is divided into actions. Requirements for each actions are estimated, and these estimates are summarized for this element of activity. The accuracy of the bottom-up estimates is determined by the size and complexity of the actions at the lower levels. Usually lesser activities increase the accuracy of estimates.
Top-down Estimating is a work element estimating method opposite to the bottom-up method.
Rolling Wave Planning is a type of planning for sequential development, in which the activity to be done in the near future is planned in detail with a deep disclosure of work breakdown structure, while far distant activity is planned with a relatively small disclosure of the work breakdown structure, but as work progresses the activities to be done in the coming time periods are clearly planned.
Earned Value Management (EVM) is a methodology for the integration of content, time and resources, as well as an objective measurement of project performance and efficiency achieved. The efficiency of the project implementation is measured by determining the planned cost of the work performed (i.e., the used capacity) and its subsequent comparison to the actual cost of the work performed (i.e. the actual cost).
Risk Breakdown Structure (RBS) is a breakdown presentation of project’s known categorized and subcategorized risks, indicating the different areas and causes of potential risks. The risk breakdown structure is often adjusted to specific types of projects.
Probability and Impact Matrix is a conventional approach adopted to classify risk as high, medium or low by comparing two risk parameters: likelihood and impact on the project objectives.
Responsibility Assignment Matrix (RAM) is a structure aligning the organizational structure of the uses the Work Breakdown Structure and helping designate the persons responsible for each project element.
Milestone Schedule is a summary level schedule displaying the timing of major project related milestones.
Analog Method is an analysis of all available data relating the implementation of previous similar projects in order to estimate the likelihood of loss. This method involves such key action aspects as an attempt to compare with a previous similar project. Information on the planned and actual deadlines is collected. If the terms did not match, the causes are analyzed, countermeasures are developed and the project is planned. The Analog Method is most widely used in risk assessment of frequently repeated projects, for example, in construction.
Expert Judgment refers to a technique in which judgment is made based upon a specific expertise that has been acquired in a specific knowledge area, or product area, a particular discipline, an industry, etc. Judgment is carried out using different methods with a focus on various aspects. The expertise can be carried out by an external group or person with a specific relevant education, skill set or knowledge. There can be several resources of expert including other divisions of executing organization, consultants, project members, including customers, professional and technical organizations and other miscellaneous industry groups.
Indicator Approach uses indicators of completed projects. For example, the interest rate method fully distributes costs in different phases. If the actual costs of the first phase are known, the rest is calculated according to the percentage distribution:
Analysis – 20%
Project – 35%
Implementation – 30%
Verification – 15%.
Poker Estimate implies the following key aspects of action:
• create a work group (developers, analysts, business representatives, and so on);
• Voice task;
• let each participant evaluate the project timeline based on his/her experience and level;
• hear each member’s opinion;
• choose the shortest and longest project term to discuss by the work group;
• correlate opinions during discussion, and make a common decision with the whole work group.
Estimated development time or hours
An important element in IT management within a software development project is to estimate the time required for product development. This issue is relevant in the solution development by both: internal resources and outsourcing. A classic example is shown in the diagram.
All this can lead to such grave consequences as disruption of the project deadline, excess of the project cost (overtime, etc.) or customer’s dissatisfaction with the product quality. To eliminate above-mentioned problems, you can use the following methods and techniques:
• Poker Estimate;
• Comparison with analog;
• Bottom up & Top down;
• Expert