Estimating Software Development Costs?

Stu Lalison asks: "I'm an MBA student (but I'm not evil, I promise!) and am working on a business plan that involves having some custom software written for a handheld computer. I've done some research into estimating the costs involved in software production, but when estimating the time involved in writing the software, it usually says 'judge on past projects.' I'm not a programmer, so I don't have any past projects to judge on. I'm wondering if the Slashdot community can give me some ballpark figures on how long it takes a professional programmer to code different parts of a program. I've identified 3 needs of my application: a front-end user interface, a database w/ search function (of about 10 megabytes of data), and integration of both of these into a (currently existing) commercial mapping application. It seems like these aren't huge tasks, but getting (even a rough) handle on their actual complexity will help me greatly. Also, how much development time would be required to port an application like this from, say, a Palm OS device to a 3G handset? Thanks in advance!"

Comments

Quick guidelines

[/dev/niall]

1) You need a detailed functional specification. Just what the application should do, not how or with what technologies.

2) You need a detailed implementation specification, which should probably be written by someone with technical experience and at least some knowledge of the application's intended use. The person(s) who write this should be able to estimate how long it will take to complete.

3) You need to double the amount of time the folks from #2 give you as an estimate. If you didn't spend a lot of effort on #1, you should probably triple the estimate as you will be adding features that will render most of #2 obsolete.

Here's one (meta-) answer

[Lumpish Scholar]

Joel Spolsky on "Painless Software Schedules"

Yeah, it's a lot of hard work. Deal with it.