What factor determines the cost of a software project?

Question

If you have $100 in your hand right now. And have to bet on one of these options. That would you bet it on? The question is:

What is the most important factor, that determents the cost of a project.

1. Typing speed of the programmers.
2. The total amount of characters typed while programming.
3. The 'wc *.c' command. The end size of the c files.
4. The abstractions used while solving the problem.

Update: Ok, just for the record. This is the most stupid question I ever asked. The question should be. Rank the list above. Most important factor first. Which are the most important factor. I ask, because I think the character count matters. Less character to change when requirements change. The faster it's done. Or?

UPDATE: This question was discussed in Stackoverflow podcast #23. Thanks Jeff! :)

Answer 1

None of those things are major factors in the cost of a project. What it all comes down to is how well your schedule is put together - can you deliver what you said you would deliver by a certain date. If your schedule estimates are off, well guess what, you're project is going to cost a lot more than you thought it would. In the end, it's schedule estimates all the way.

Edit: I realize this is a vote, and that I didn't actually vote on any of the choices in the question, so feel free to consider this a comment on the question instead of a vote.

Answer 2

From McConnell:

http://www.codinghorror.com/blog/archives/000637.html

[For a software project], size is easily the most significant determinant of effort, cost, and schedule. The kind of software you're developing comes in second, and personnel factors are a close third. The programming language and environment you use are not first-tier influences on project outcome, but they are a first-tier influence on the estimate.

1. Project size
2. Kind of software being developed
3. Personnel factors

I don't think you accounted for #3 in the above list. There's usually an order of magnitude or more difference in skill between programmers, not to mention all the Peopleware issues that can affect the schedule profoundly (bad apples, bad management, etc).

Answer 3

I thing the largest amount on large projects are testing and fixing the bugs and fixing misinterpretation of the requirements. First you need write tests. Than you fix the code that the tests run. Than you make the manual tests. Then you must write more tests. On a large project the testing and fixing can consume 40-50% of time. If you have high quality requirements then it can be more.

Answer 4

Characters, file size, and typing speed can be considered of zero cost, compared to proper problem definition, design and testing. They are easily an order of magnitude more important.

Answer 5

The most important single factor determining the cost of a project is the scale and ambition of the vision. The second most important is how well you (your team, your management, etc.) control the inevitable temptation to expand that vision as you progress. The factors you list are themselves just metrics of the scale of the project, not what determines that scale.

Answer 6

Of the four options you gave, I'd go with #2 - the size of the project. A quick project for cleaning out spam is going to be generally quicker than developing a new word processor, after all.

After that I'd go with "The abstractions used while solving the problem." next - if you come up with the wrong method of solving the problem, either wrong because of the logic being bad or because of a restriction with the system - then you'll definitely spend more money on re-design and re-coding what has already been done.