Rating Very Very Extra Cost Drivers Low Low Nominal High High High Product Attributes Required software reliability Database size Product complexity Computer Attributes Execution time constraint Main storage constraint Virtual machine volatility* Computer turnaround time Personnel Attributes Analyst capabilities Applications experience Programmer capability Virtual machine experience* Programming language experience Project Attributes Use of modern programming practices Use of software tools Required development schedule *For a given software product, the underlying virtual machine is the complex of hardware and software (operating system, database management system) it calls on to accomplish its task. COCOMO Effort Adjustment Factors [Project Estimation & Planning, p. 21]

Example COCOMO EAF Ratings for Communications Software Effort Cost Drivers Situation Rating Multiplier Required software reliability Serious financial consequences High 1.15 of software fault Database size 20,000 bytes Low 0.94 Product complexity Communications processing Very high 1.30 Execution time constraint Will use 70% of available time High 1.11 Main storage constraint 45K of 64K store (70%) High 1.06 Virtual machine volatility Based on commercial Nominal 1.00 microprocessor hardware Computer turnaround time Two hour average turnaround time Nominal 1.00 Analyst capabilities Good senior analysts High 0.86 Applications experience Three years Nominal 1.00 Programmer capability Good senior programmers High 0.86 Virtual machine experience Six months Low 1.10 Programming language Twelve months Nominal 1.00 experience Use of modern programming Most techniques in use High 0.91 practices over one year Use of software tools At basic minicomputer tool level Low 1.10 Required development Nine months Nominal 1.00 schedule

Distribution (Repartition) of Effort, Schedule and Cost [Project Estimation and Planning, pp. 22,23] Notes: i) 3 distinct distributions are given by software engineering activity. The activities are different over the 3 tables, but can be related. All figures are given as percentages, and may need to be converted into person-months, weeks, and $1,000 for example. ii) The requirements and planning effort and schedule are included in the high-level design effort and schedule. High-level design begins at the same time as requirements and planning in the COCOMO model, and the requirements and planning activities are revisited over the course of the project, and the corresponding effort and schedule are not separated from the other activities. However, in the cost model [p. 23], requirements are kept as a separate cost. iii) If the approximate (burdened) cost of one person month is identical over all project personnel, the table on p. 23 can be used (as on p. 26) as a distribution (repartition) of effort as well. iv) For Assignment 1, Part 1 explain what your distribution of cost is based on [p. 22 or 23].

Effort versus Number of Persons Productivity (L) in LOC/PM diminishes as the number of people (P) involved L = 777 P -0.5 Development Time in COCOMO is estimated as T = 2.5 E 0.38 The number of persons required will vary over the duration of the project (according to a Rayleigh curve (look it up)