The key to making the unmeasurable measurable is models. A model is an abstraction, which strips away unnecessary details and views an entity or concept from a particular perspective. Models allow us to focus on the important parts, ignore those that are irrelevant, and hypothesize and reason about an entity. Models make measurement possible.

We must have models of whatever we want to measure. For example, say we want to know how much of the total system development effort is testing. To determine that, we need a model of both the overall development process and the testing process, which specifies when testing starts and when it ends, what is included, and the number of people involved. If our model starts with unit test by the programmer, it is a different model and will give different results than one that includes only system test.

There are three types of models you can use: text, diagrammatic, and algorithmic that is, words, pictures, and numbers.

This entry was posted on Sunday, October 12th, 2008 at 5:29 pm and is filed under Estimation.