Thanks, in my understanding both Thomson reuters impact factor and scopus citescore means good quality but still many universities consider only ïmpact factor"as valid.
CiteScore is actually a Scopus impact factor. It is based on three- years window (for publications), while the impact factor is based on a two-years window.If you would like to choose between the two, than please consider this; usually a longer publications' window indicates more stability (less fluctuations), but the impact factor which is based on two-years window relies on a very selective quality data. A third way could be to rank the journals by both methods and compare the results.
Major difference between CiteScore and Journal Impact Factor:
CiteScore calculation is based on Scopus data, while Impact Factor is based on Web of Science data.
CiteScore uses a 3-year window while Impact Factor adopts a 2-year window.
CiteScore includes all document types indexed by Scopus, include articles, reviews, letters, notes, editorials, conference papers, etc. while Impact Factor only includes "citable documents" which are articles and reviews.