In this article, we provide a new procedure to test for at‐most‐
frakturm changes in the time‐dependent regression model
yt=boldxt⊤bold-italicβt+et,1⩽t⩽T, that is, β1 = β2 = ⋯ = βT under the no‐change null hypothesis against the alternative
yt=bold-italicxt⊤bold-italicβ(i)+et, if
ki−1∗