This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ch time as the same person working full time. However, as additional resources are added, projects can experience communication overload, which reduces productivity and causes production to improve proportionally less than the increase in resource. .5 Resource capabilities. The duration of most activities will be significantly influenced by the capabilities of the human and material resources assigned to them. For example, if both are assigned full time, a senior staff member can generally be expected to complete a given activity in less time than a junior staff member. .6 Historical information. Historical information on the likely durations of many categories of activities is often available from one or more of the following sources: Project files--one or more of the organizations involved in the project may maintain records of previous project results that are detailed enough to aid in developing duration estimates. In some application areas, individual team members may maintain such records. Commercial duration estimating databases--historical information is often available commercially. These databases tend to be especially useful when activity durations are not driven by the actual work content (e.g., how long it takes concrete to cure; how long a government agency usually takes to respond to certain types of requests). Project team knowledge--the individual members of the project team may remember previous actuals or estimates. While such recollections may be useful, they are generally far less reliable than documented results. .7 Identified risks. The project team considers information on identified risks (see Section 11.2) when producing estimates of activity durations, since risks (either threats or opportunities) can have a significant influence on duration. The project team considers the extent to which the effect of risks is included in the baseline duration estimate for each activity, including risks with high probabilities or impact. 6.3.2 Tools and Techniques for Activity Duration Estimating .1 Expert judgment. Expert judgment is described in Section 22.214.171.124. Durations are often difficult to estimate because of the number of factors that can influence them (e.g., resource levels, resource productivity). Expert judgment guided by historical information should be used whenever possible. If such expertise is not available, the estimates are inherently uncertain and risky (see Chapter 11, Project Risk Management). .2 Analogous estimating. Analogous estimating, also called top-down estimating, means using the actual duration of a previous, similar activity as the basis for estimating the duration of a future activity. It is frequently used to estimate project duration when there is a limited amount of detailed information about the project (e.g., in the early phases). Analogous estimating is a form of expert judgment (described in Section 126.96.36.199). Analogous estimating is most reliable when a) the previous activities are similar in fact...
View Full Document
- Fall '13
- The American