Research projects

Project CEMAPRE internal

TitleStructural changes in the variance of time series (cont.)
ParticipantsRui Louro, Nuno Sobreira (Principal Investigator)
SummaryThis project continues the same project with the same name and description of the previous year. It
is a project with Phd student Rui Louro. This project is advancing (although the progress should be
faster). The idea is the following: time series can be affected by structural changes in variance,
which if unaccounted for can have detrimental effects in the analysis and modeling steps. One paper
develops an R package named varbreaks, which contains the most common tests for detecting the
presence of structural changes in variance. Tests for single and mutiple breaks are included within
the package, as well as a procedure to deal with potential breaks in the conditional mean. A
detailed description of the various tests, computational implementation and examples are provided by
this paper. Another paper compares the finite sample properties of the most common tests to detect
the presence of structural changes in the variance of a given time series. We pay particular
attention to cases where structural changes can occur both in the conditional mean and variance
processes.