  Focusing specifically on the recently retracted Nature 2018 Zhang et al. work
[Zhang et al., Nature (2021)] and the related recently available correctly
analyzed data from this Delft experiment [Zhang et al., arXiv:2101.11456
(2021)], we discuss the general problem of confirmation bias in experiments
verifying various theoretical topological quantization predictions. We show
that the Delft Majorana experiment is most likely dominated by disorder, which
produces trivial (but quite sharp and large) zero-bias Andreev tunneling peaks
with large conductance $ \sim 2e^2/h $ in the theory, closely mimicking the
data. It is possible to misinterpret such disorder-induced zero-bias trivial
peaks as the apparent Majorana quantization, as was originally done in 2018
arising from confirmation bias. One characteristic of the disorder-induced
trivial peaks is that they manifest little stability as a function of Zeeman
field and tunnel barrier, distinguishing their trivial behavior from the
expected topological robustness of non-Abelian Majorana zero modes. We also
analyze a more recent nanowire experiment [Yu et al., Nature Physics (2021)]
which is known to have a huge amount of disorder, showing that such highly
disordered nanowires may produce very small above-background trivial peaks with
values $ \sim 2e^2/h $.
