Posted on December - 07 - 2008
A Picture is Emerging
Keeping up with the idea that we’re doing software estimating to create a software package, let’s go ahead and give a long look at our intended project. The first question you’re going to have to ask yourself is how big is this project going to be?
If this is code, how much is necessary? How much can be recycled?
If you’re writing new software, one of the key determining factors for all other estimates is going to be the sheer size of the project as measured in Source Lines of Code (SLOC). This sounds like an obvious place to start, but whether your under the influence of inspiration or the crush of deadlines, a project can easily bloat out of control.
Though you’re likely going to want to restrain your SLOC to the lowest number of lines possible, you’re going to want to give yourself a cushion in your initial SLOC estimate. One popular estimation method is to draw up three numbers, the least possible number of lines, the probable or likely number, and the outside largest number.
Once you know the likely sizes of your project, you can then start to whittle down the involved labor. Is there Commercial-off-the-shelf (COTS) software that can be incorporated to help achieve the desired solution? Have you developed prior pieces of code, modules that can be incorporated? These pre-existing solutions will have an impact on your SLOC, but also the cost and time of the project, proving that while SLOC might grow or contract, the relationship between SLOC and the total cost of the software is not a solely dependent relationship.
Coming up with these answers ahead of time helps to prepare the overall software estimate by providing a more complete picture of the desired project. Understanding the source before you start it, and determining the best courses of action regarding COTS, FOSS, and pre-existing code solutions is a good method for creating shortcuts and cost savings well ahead of when they’ll actually be needed. Doing so is a lot like plotting a vacation on a map before you start the trip. Even though you have never been where you’re going, you’ll have a fleshed out idea of where you’re going, how long the trip is going to take, and whether anyone has been nice enough to already build bridges for you.
And, once you have that knowledge, you’re much better suited to answer the proverbial question, “Are we there yet?”
