Software metrics and estimating

Question: What problems are there in basing project estimates on how many lines of code the project will have to produce?

Question: What do we know about a project at initiation stage?

Function point analysis

FPA looks at each transaction in a design, and assigns a score. These are added up to give the "logic size" of the application. Factors affecting logic size are:

no. of attributes in inputs and outputs
no. of entities referenced by processing
type of transaction

The complexity of the application

distributed functions? multiple sites?
interactive? ease of use?

Other factors that affect productivity on a specific project are taken into account, such as staff skills

Industry standards for productivity given (how many function points per hour). Replace these with your own as you gain experience

Improving the estimating process

Recommendations:

Have as many (appropriate) people involved as is practical
Guess as little as possible

the more you know, the less you have to estimate

Compensate for optimism
Compare your figures with industry norms
Use a method such as COCOMO or FPA, and calibrate it for your environment
Allow for overheads, administration, meetings, time to gain approval from senior management, changes to user requirements, etc.
Hopelessly optimistic timetables are a de-motivator - if you want projects completed sooner, give staff realistic targets (Peopleware, DeMarco & Lister, 1987)