Measure or Dimension?
From this article on the official guide it said 'For instance, you might calculate the Sum of “Sales” for every “State”. In this case, the Sales field is acting as a measure because you want to aggregate the field for each state. But measures could also result in a non-numeric result. For instance, you might create a calculated measure called “Sales Rating” that results in the word “Good” if sales are good and “Bad” otherwise. In this case the “Sales Rating” field acts as a measure even though it produces a non-numeric result. It is considered a measure because it is a function of the dimensions in the view'.
(Link: http://onlinehelp.tableau.com/current/pro/online/windows/en-us/datafields_typesandroles_dataroles_dimensionmeasure.html )
I used the below query to create the field of 'Sales Rating':
IF [Sales] > 2000 THEN 'good'
ELSEIF [Sales] <=2000 AND [Sales]>500 THEN 'medium'
ELSEIF [Sales]<= 500 THEN 'ok'
It automatically sets the Sales Rating to dimension instead of measure. So the official guide of Tableau is incorrect?
How did you interpret the last sentence from the guide 'It is considered a measure because it is a function of the dimensions in the view'?