N MS Offset Trendis the difference in the share ofmarket share between periods N and N-1 (N-1 in this case being the previous adjacent period).
Depending on the analyses, the comparison period will be :
Weekly the previous week (s37 vs. s36)
Monthly The previous month (September 2017 vs. August 2017)
Quarterly Previous quarter (July 2017 to September 2017 vs. April 2017 to June 2017)
Annual Previous year (2017 vs. 2016)