Analytical Calendar The Story | The Index Page
2023-05-12
Analytical Calendar
Date Comparison
Date comparison is another typical
operation in data analytics. Firstly, a time period is selected and then it is
compared with another time period. There are two typical methods to do the
comparison: one is to make use of the comparison unit and comparison range. And
the other is simply to select the required period of time.
Comparison Unit and Range
Comparison unit and range is to provide a
date unit and a number as the range. The comparison unit consists of all the
date components including year, quarter, month, week and date. Comparison range
is an integer that describes the duration for the comparison unit, i.e. how
many comparison unit before. E.g. Comparison Unit = Month and comparison range
= 2, it means 2 month before. Comparison starts from one in general.
For example, compare 1 year before has a
general term called Year-Over-Year (YOY) comparison where year is the
comparison unit and 1 is the range. Another example, compare 1 month before has
a general term called Month-Over-Month (MOM) comparison where month is the
comparison unit and 1 is the range.
Custom Comparison
Custom comparison is less complicated than
the comparison unit and range. It only requires picking a start date and an end
date to indicate a period of time. All dates included with the start (inclusive)
and end dates (inclusive) will be the dates required for comparison.
The majority of the time, we require custom
comparison to accommodate irregular date ranges for specific needs for analysis.
For example, Lunar new year has different dates each year and comparison unit
and range cannot help in this case. The only option is to directly select the
specified range of dates. Other examples like, seasonal periods, non-fixed date
holidays, Black Friday, etc. are all required using custom comparison.
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