Planning

Question 1

part a.
In an iterative life cycle, explain two components of the project management plan that

part (b) Explain three different methods of estimation in projects.

Answer 1

part a
Because not all requirements are detailed up front, detailed project planning as carried out in a linear life cycle is not possible. There will be a time box created so the first component to consider is the duration of the time box. This will be an arbitrary value. It should be long enough to create some usable functionality.

The second consideration is the amount of resources to deploy. This will then allow for planning what functionality will be deliver by the time box. Once these are decided then a baseline resource schedule can be created and a baseline budget determined

part b
Choose three from the following: Parametric, Analogous , Analytical and Delphi

1 Analytical
Also called bottom up, this method is based on the WBS. All the individual lower level tasks in the WBS are estimated independently and then rolled up to produce the project estimates. This is a laborious method and its accuracy is dependent on having a correct WBS. However it is the most accurate way of estimating. It is sometimes known as the definitive estimate.

2 Analogous Estimating
This is also called Top Down or Historic estimating. It simply involves using experience from similar projects carried out in the past. It takes the overall costs and timescales for similar projects and adjusts them for size and complexity. The danger is that previous projects may have been inefficient and/or badly managed. Comparative estimating can also be used at task level to support bottom up.

3 Parametric Estimating
Parametric estimating uses a mathematical model or formulae to produce project estimates based on input parameters. It is usually based on historical data. Simple examples are square metres in construction and lines of code in software development. Quantity Surveyors make extensive use of parametric estimating.

Question 2

Part (a) Explain the prerequisites required for each of the following three estimating methods:

1. Comparative
2. Bottom up/Analytical
3. Parametric

part (b) State four practical problems of initial estimates for a project with a long timescale.

Answer 2

1) Comparative:
• Your project must have elements that are comparable with elements of previous projects.
• Actual data from previous project needs to have been collected and stored for access.
• The circumstances around the previous estimate should have been recorded to ensure that comparisons are valid.

2) Bottom Up
• There needs to be in place a complete work breakdown structure that identifies all the work of the project.
• There needs to be an accurate estimate for each lowest level task or work package.

3) Parametric
• The work to be done must be suitable for parametric estimating e.g. consisting of elements of scalable work such as laying bricks or plastering walls.
• There must exist standardised data based on previous actuals e.g. what is the expected time for a trained bricklayer to lay 100 bricks?

1) There may be no suitable historic data for comparative estimating.
2) There may be no detailed work breakdown structure for work far out in the future hence bottom up cannot be fully carried out
3) There may be no standardised data available or future work is not planned in enough detail to apply parametric estimating.
4) With a protracted timescale many things can occur in the future to make estimates invalid such as unexpected events, evolution of requirements or new technology.