Summary

Establish and maintain estimates of work product and task attributes.

Description

Size is the primary input to many models used to estimate effort, cost, and schedule. Models can also be based on other attributes such as service level, connectivity, complexity, availability, and structure.

 

Examples of attributes to estimate include the following:
  • Number of requirements
  • Number and complexity of interfaces
  • Volume of data
  • Number of risk items
  • Number of service levels
  • Availability of services, by service level (e.g., turnaround time, operational availability ratio, number of calls the help desk should be able to handle per hour)
  • Number of stakeholders affected by a service level
  • Experience of work group participants
  • Team velocity or productivity
  • Geographic dispersal of work group members
  • Proximity of customers, end users, and suppliers


The estimates should be consistent with requirements to determine the effort, cost, and schedule for the work. A relative level of difficulty or complexity should be assigned for each size attribute.

Example Work Products



  1. Size and complexity of tasks and work products
  2. Estimating models
  3. Attribute estimates


Subpractices



1. Use appropriate methods to determine the attributes of the work products and tasks to be used to estimate resource requirements.

Methods for determining size and complexity should be based on validated models or historical data.

The methods for determining attributes evolve as the understanding of the relationship of service development and delivery characteristics to attributes increases.



2. Estimate the attributes of work products and tasks.

 

Examples of tasks for which size estimates are made include the following:
  • Service system development and delivery
  • Service system monitoring
  • Preventative maintenance or repair
  • Training in operations
  • Incident management and resolution
  • Monitoring for and addressing obsolescence
  • Updating equipment and supplies used by service teams
  • Logistical support
  • Facilities maintenance
  • System disposal