data

There are four types of data, or levels of measurement, that show up in databases. Everything that goes into the database or shows up on a survey corresponds to one of these levels, from address fields to income. It is important to recognize which is which, because not all measures can be used on each of the types, and it is easy to make the wrong conclusions about the data by using the wrong measures.

One of the things that can confuse a lot of people who are new to data analysis is the concept of "data is data." That is to say, so long as I have the data, the topic that I am reporting on does not matter from the standpoint of reporting. It doesn't matter if I am reporting on income or velocity, revenue or shuttle launches.