Experiment!: Planning, Implementing and Interpreting

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Phase II: Data Collection

Thinking is more interesting than knowing, but not as interesting as looking.

—J.W. von Goethe

In this chapter we will discuss two aspects of the data collection process. The first has to do with what we measure and this discussion builds on the contents of the last chapter. We must choose variables that are connected with our research question in a meaningful way. If they are not, it is difficult to draw meaningful conclusions from the data. The other aspect has to do with how we measure. It is important to make sure that the data are of sufficient quality to support the conclusions that we wish to draw and we ensure this by using proper measurement systems and procedures. We are going to discuss how to develop a measurement system, how to identify sources contributing to measurement uncertainty and how to quantify the uncertainty. Finally, we will go into the benefits of making a data collection plan.