You are correct!
Unfortunately, there are many Bjorn Luzers out there, who do not take the time to properly define what they are measuring. This failure results in attribute and Pareto charts that aren’t worth the paper they are printed on.
To understand operational definitions more completely, refer to the PDF file below. It is a chapter from Practical Tools for Continuous Improvement: Volume 1 (ed., Michael J. Cleary, Ph.D. and Jacqueline D. Graham, Ph.D).