Step-3: Additive vs. Non-Additive facts

 
  • Additive facts are easy to work with
    • Summing the fact value gives meaningful results
    • Additive facts:
      • Quantity sold
      • Total Rs. sales

 

    • Non-additive facts:
      • Averages  (average sales price, unit price)
      • Percentages  (% discount)
      • Ratios (gross margin)
      • Count of distinct products sold

 

Month

Crates of

Bottles Sold

May

14

Jun.

20

Jul.

24

TOTAL

58

 

Month

% discount

May

10

Jun.

8

Jul.

6

TOTAL

24%  ← Incorrect!

 

 

There can be two types of facts i.e. additive and non-additive. Additive facts are those facts which give the correct result by an addition operation. Examples of such facts could be number of items sold, sales amount etc. Non-additive facts can also be added, but the addition gives incorrect results. Some examples of non-additive facts are average, discount, ratios etc. Consider three instances of 5, with the sum being 15 and average being 5. Now consider two numbers i.e. 5 and 10, the sum being 15, but the average being 7.5. Now if the average of 5 and 7.5 is taken this comes to be 6.25, but if the average of the actual numbers is taken, the sum comes to be 30 and the average being 6. Hence averages, if added gives wrong results. Now facts could be averages, such as average sales per week etc, thus they are perfectly legitimate facts.

 

      

 

 

Previous

 

 

TOC

 

 

Next