  We show that, in addition to the counting of canonical dimensions, a counting
of loop orders is necessary to fully specify the power counting of Standard
Model Effective Field Theory (SMEFT). Using concrete examples, we demonstrate
that considering the canonical dimensions of operators alone may lead to
inconsistent results. The counting of both, canonical dimensions and loop
orders, establishes a clear hierarchy of the terms in SMEFT. In practice, this
serves to identify, and focus on, the potentially dominating effects in any
given high-energy process in a meaningful way. Additionally, this will lead to
a consistent limitation of free parameters in SMEFT applications.

High Energy Physics - Phenomenology