Psychologists need to be able to test for the absence of an effect.
Using the Two-One-Sided Tests (TOST) procedure, researchers can easily
test whether the observed effects are too small to be meaningful. By
specifying a smallest effect size of interest (SESOI) researchers test
whether observed effects are surprisingly closer to zero, assuming there
was an effect the consider meaningful. We explain a range of approaches
to determine the SESOI in psychological science, and provide detailed
examples of how equivalence tests should be performed and reported.