The program is not the product

Managers want programs to be like the output of a factory. Install the right robots and tooling, start the process, and good software comes out the end.

WRONG WRONG WRONG WRONG WRONG WRONG WRONG WRONG WRONG WRONG!!!!!! (Can you tell I disagree?)

Nearly everyone who makes the factory analogy misses a very fundamental point: the program is not the product. For one thing, unless you work for a software company selling shrink-wrapped software products you aren't ever selling the program. Conventional wisdom says most programmers actually work for internal IT, so it's safe to say most programs are never sold.

Businesses don't want programs, they want credit reports ... and loan contracts ... and title searches ... and purchase orders ... and claim forms ...

So what is the right analogy? The program is the assembly line! So measuring bugs in the program is wrong. Even comparing compiling to manufacturing -- which is better than comparing programming to manufacturing -- is wrong. What you should be looking at is the output produced by the program.

Is your program a website? Measure the number of pages it can produce per unit time, without error. Is it an editor? Measure the number of pages it can spell-check per unit time, and with what accuracy.

When measuring the output of a manufacturing process, you literally shouldn't care what the process looks like, nor what tools are used, so long as it consistently produces the same output. This is not to say the process and tools don't matter. A bad process may be prone to unexpected failure. Tools may be harder to maintain or have a shorter service life. You may be locked into a service contract with the manufacturer. And coincidentally [ahem] all these factors apply to software.

So yes, programming can be compared to manufacturing. As long as you remember that the program is not the product, the program is the assembly line.