I'm writing my thesis in psychological research. On one variable I did a tercile split because in other empirical work it is often done so and literature says that most likely there will be effects on the extremer parts of the distribution. In analyses then, I will use a dummy-coded variable.
In which section I should report the tercile split? Directly in methods section when I describe the measure itself? Or little bit later in analysis plan where I mention the statistical methods (e.g. regression) used?
Edit: I have to mention that the scale was a 10 point scale but in sample only values between 3 to 7 were observed, so this was also an argument for categorizing the variable.