  This note corrects a mistake in the paper "consistent cross-validatory
model-selection for dependent data: $hv$-block cross-validation" by Racine
(2000). In his paper, he implied that the therein proposed $hv$-block
cross-validation is consistent in the sense of Shao (1993). To get this
intuition, he relied on the speculation that $hv$-block is a balanced
incomplete block design (BIBD). This note demonstrates that this is not the
case, and thus the theoretical consistency of $hv$-block remains an open
question. In addition, I also provide a Python program counting the number of
occurrences of each sample and each pair of samples.
