Calculating Previous Year Marketing Calendar Values with DAX

Written by Dan English

Saturday, 25 September 2010 21:48

When it comes to reporting typically we will use the common calendar year that starts on January 1 and goes through December 31 with the standard months. We might even be faced with a fiscal calendar that starts on July 1 and ends June 30 the following year. In both of these cases we are sticking with the set days in the months and are not doing anything special. But what happens when we start to use a custom calendar for marketing or retail purposes like a 445, 454, 544, or possibly 13 periods of 4 weeks each? Will this have any impact on how we need to create our metrics to report on our data? The answer – Yes. Because in this case we are not simply evaluating September 1 of this year to September 1 of last year. Nope. We are actually evaluating it to September 2 of last year which is the same day of the week.