Costing Techniques

The optimistic estimate of number of lines of code LOC for a given function is based upon the analyst's previous experience. So are the most likely estimate and pessimistic estimate of LOCs. Based upon these, the expected number of lines of code Le, and the Deviation Ld, can be derived as follows: Le = (a + 4m + b)/6 and Ld = (b - a)/6 ( Ld = ( sum(((bi-ai)/6)2))0.5 for multiple entries in a table).

The $/line is the cost per line, and the Line/month is the productivity for a particular function. From the expected LOC and the $/line we can estimate the cost. From the expected LOC and the Line/month we can estimate the person-months of the project.

The Deviation Ld enables us to give a range of estimates. for example, 

Expected LC = 33360
Deviation = 1100

Therefore

68% range = 32260 to 34460 LOC
99% range = 26760 to 39960 LOC