Establish and maintain estimates of work product and task attributes.
Size is the primary input to many models used to estimate effort, cost, and schedule. The models can also be based on inputs such as connectivity, complexity, and
structure.
Examples of types of work products for which size estimates are made include the following:
· Deliverable and nondeliverable work products
· Documents and files
· Operational and support hardware, firmware, and software
Estimation methods include using historical acquirer and supplier data and standard estimating models to compare projects of similar complexity. Where historical size data are not available, develop an estimate based on the understanding of the design of similar products.
Estimation models can be built based on historical data as part of organizational process performance, and estimates for any project can be validated using these
models.
Refer to the Organizational Process Performance process area for more information about process-performance models.
Examples of size measures include the following:
· Number of functions
· Function points
· Source lines of code
· Number of classes and objects
· Number of requirements
· Number and complexity of interfaces
· Number of pages
· Number of inputs and outputs
· Number of technical risk items
· Volume of data
· Number of logic gates for integrated circuits
· Number of parts (e.g., printed circuit boards, components, and mechanical parts)
· Physical constraints (e.g., weight and volume)
The estimates should be consistent with project requirements to determine the project’s effort, cost, and schedule. A relative level of difficulty or complexity should be assigned for each
size attribute.
Typical Work Products
1. Technical approach
2. Size and complexity of tasks and work products
3. Estimating models
4. Attribute estimates
Subpractices
1. Determine the technical approach for the project.
The technical approach defines a top-level strategy for development of the product. It includes decisions on architectural features, such as distributed or client/server; state-of-the-art or
established technologies to be applied, such as robotics, composite materials, or artificial intelligence; and breadth of the functionality expected in the final products, such as safety, security, and ergonomics.
The technical approach provides a basis for interoperability and supportability of the technical solution developed by the supplier.
2. 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.
Examples of attributes include the following:
· Maturity of the technology specified in the technical solution
· Amount and complexity of the work potentially assigned to suppliers
· Number of locations where the product is to be installed
The methods for determining attributes evolve as the understanding of the relationship of product characteristics to attributes increases.
Examples of current methods include the following:
· Number of logic gates for integrated circuit design
· Lines of code or function points for software
· Number and complexity of requirements for systems engineering
· Number of square feet for standard-specified residential homes
3. Estimate the attributes of work products and tasks.
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CMMI-ACQ 1.2
4. 
SP 1.3 Establish Estimates of Work Product and Task Attributes