  This paper is an excerpt of an early version of Chapter 2 of the book
"Validity, Reliability, and Significance. Empirical Methods for NLP and Data
Science", by Stefan Riezler and Michael Hagmann, published in December 2021 by
Morgan & Claypool. Please see the book's homepage at
https://www.morganclaypoolpublishers.com/catalog_Orig/product_info.php?products_id=1688
for a more recent and comprehensive discussion.
