used especially at the beginning of a sentence when the next thing that is mentioned is compared with sth in the previous sentence :
By comparison, expenditure on education increased last year.
used especially at the beginning of a sentence when the next thing that is mentioned is compared with sth in the previous sentence :
By comparison, expenditure on education increased last year.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005