Premium
FINITE SAMPLE EFFECTS OF PURE SEASONAL MEAN SHIFTS ON DICKEY–FULLER TESTS: A SIMULATION STUDY
Author(s) -
DA SILVA LOPES ARTUR C. B.
Publication year - 2008
Publication title -
the manchester school
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.361
H-Index - 42
eISSN - 1467-9957
pISSN - 1463-6786
DOI - 10.1111/j.1467-9957.2008.01074.x
Subject(s) - econometrics , unit root , lag , economics , statistics , mathematics , sample (material) , affect (linguistics) , selection (genetic algorithm) , sample size determination , thermodynamics , computer science , psychology , physics , computer network , communication , artificial intelligence
In this paper, it is demonstrated by simulation that, contrary to a widely held belief, pure seasonal mean shifts—i.e. seasonal structural breaks which affect only the seasonal cycle—really do matter for Dickey–Fuller long‐run unit root tests. Both size and power properties are affected by such breaks but using the t ‐sig method for lag selection induces a stabilizing effect. Although most results are reassuring when the t ‐sig method is used, some concern with this type of breaks cannot be disregarded. Further evidence on the poor performance of the t ‐sig method for quarterly time series in standard (no‐break) cases is also presented.