Companion package of Carrion-i-Silvestre & Sansó (2026):
"Testing for Constant Unconditional Variance in Heavy-Tailed Time Series". It implements the Modified
Iterative Cumulative Sum of Squares Algorithm, which is an extension of
the Iterative Cumulative Sum of Squares (ICSS) Algorithm of Inclan and Tiao (1994), and it checks for changes in the
unconditional variance of a time series controlling for the tail index of
the underlying distribution. The fourth order moment is estimated non-parametrically
to avoid the size problems when the innovations are non-Gaussian (see, Sansó et al., 2004).
Critical values and p-values are generated using a Generalized Extreme Value distribution approach.
References
Carrion-i-Silvestre J.J & Sansó A (2026)