Software Psychology

The Law of Lossy Requirements by Bruce Nielson

Lossy Compression

In computer science, compression is an indispensible tool. Anyone familiar with .zip files knows what I mean. Interestingly, there are two kids of compression, lossless and lossy. Lossless compression is like .zip compression, you put a file of, say, 100kb in and the end result is a file of, say, 50k. But when you reverse the process, you get back your original 100kb file.

Lossless compression relies on the fact that in real life information contains patterns. Just imagine taking this post and finding the most common used words in it. Then replace the most common word with a the tag “<1>” and the next most common with “<2>”, etc. The end result would generally be a smaller file, yet by replacing “<x>” with the original words you could recover the original file in its entirety.

I used to wonder what possible use lossy compression could ever be. Why in the world would I ever want to save off a compressed version of my files if I couldn’t get them back to their original state ever again?

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Proper Use of Overtime by Bruce Nielson

How Do You Estimate for That?! by Bruce Nielson

Does Robert Glass’ Formula for Estimation Success Actually Work? by Bruce Nielson

What are Water Breathers? by Bruce Nielson

In Robert Glass' excellent book, Fact and Fallacies of Software Engineering, one of his “facts” (I.e. Qualified opinions) if that “Most software estimates are preformed at the beginning of the life cycle... before the requirements are defined and thus before the problem is understood.”

He goes on to say that, unlike many of his “facts” in the book, there seems to be no controversy on this one; there seems to be general intellectual agreement that we lock in on estimates too soon. This being the case, he says, “Someone should be crying out to change things. But no one is.”

He then adds:

At the very least, you need to know what problem you are to solve. But the first phase of the life cycle, the very beginning of the project, is about requirements determination. ... Put more succinctly, requirements determination is about figuring out what problem is to be solved. How can you possibly estimate solution time and cost if you don't yet know what problem you are going to be solving?

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