Software development is like construction

I am going to depart from my usual facts-only entries because I thought this was funny. I was told again recently that software development is like construction, and that the software development profession should be able to "grow up" and create predictable bug-free software. This was the gist of my reply:

I have heard the comparison between software development and construction a number of times. It's an alluring analogy for those that don't really understand software development. Maybe you've heard it used by a manager looking to explain why getting software done on time, with all the features done correctly shouldn't be so hard.

Software development is like building a bridge. You have a need for which you make a plan, and then set about lining up the materials and manpower necessary to put the plan into action. Construction projects experience set-backs, but through proper project management (the assignment of new resources, overtime hours, etc) the project gets done - and you have a bridge every time.

Yes, software development is just like that. It's just like building a bridge where 4 months into the project the city engineer declares that no bridge shall be fewer than 200 feet, and you were building a 185 ft. bridge. And, after increasing the size of the bridge to 200 feet - resetting some of the primary support posts, adding a few people to the project, and purchasing new materials - you realize that good old Portland cement won't work for this bridge. You look for the proper materials in the marketplace, and find a few companies working on some experimental materials. They aren't selling anything yet, but are happy to let you have their recipes. So, you get your guys working on this new compound while you finish the foundation and supports. After 2 months, they decide they have it and you go back to work pouring the street. About this time, the mayor decides that no cars will be allowed in the city, and your bridge is no longer necessary.

Software development is just like construction. Another person once told me that we can call software developers 'engineers' when they can be sued for doing their job incorrectly. I say, you can sue me for the software when you can tell me exactly what you want.

Of course, there are lots of ways to improve the process of software development and in the last few years I think a lot of progress has been made. However, software is never a bridge. That's hardware. People like software because it becomes whatever they want. I think we just have to figure out how to help people better explain what they need.