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IBM Cognos 8 Platform => COGNOS 8 => Report Studio => Topic started by: JoelR on 05 Sep 2007 02:36:43 PM

Title: How to make an Average of Averages- Thank you
Post by: JoelR on 05 Sep 2007 02:36:43 PM
I have a report that gives averages of projected work orders compared to completed work orders for each of our departments, individually.  This same report gives the averages for all of the departments as a whole.  I would like to average the averages for all of the individual departments.  For example,
1094/ 1123 = 97%
435/ 444 = 98%
126/ 134 = 94%
66/ 66 = 100%
216/ 242 = 89%
99/ 99 = 100%
354/ 368 = 96%
191/ 194 = 98%
36/ 41 = 88%
112/ 132 = 85%
The summary average is 2729/ 2843 = 96% which is different than the average of 97%, 98%, 94%, 100%, 89%, 100%, 96%, 98%, 88%, 85% which is 95%
Title: Re: How to make an Average of Averages- Thank you
Post by: Suraj on 06 Sep 2007 05:18:26 PM
can't you simply create a calculated item for it?
such as:
total(completed orders for report)/total(projected orders for report)
I think that should work fine.
Title: Re: How to make an Average of Averages- Thank you
Post by: JoelR on 18 Sep 2007 09:58:32 AM
I'm afraid not, the "total(completed orders for report)/total(projected orders for report)" is what I meant by "the summary average is 2729/ 2843 = 96% which is different than the average of 97%, 98%, 94%, 100%, 89%, 100%, 96%, 98%, 88%, 85% which is 95%".
Title: Re: How to make an Average of Averages- Thank you
Post by: rockytopmark on 18 Sep 2007 12:30:54 PM
But the calculation of total(completed orders for report)/total(projected orders for report) gives you the ACTUAL average for all departments.  The average of the averages is not very worthwhile since they are not weighted based on activity.

Here is an example, very simplified to push across my point.

You have 2 departments...

Dept-1:  100/100 = 100%
Dept-2:        1/2 = 50%


Possible average calcs:
-----------------------------------------------------------------------------
Total method:            101/102 = 99%
Avg of Avg's method:  100 + 50 / 2 = 75%

Of these 2 possiblilities of an Average, what value is accurate and realistically worth anything?
Title: Re: How to make an Average of Averages- Thank you
Post by: JoelR on 20 Sep 2007 02:57:44 PM
I know what you are saying, the average of the averages is not very worthwhile since they are not weighted based on activity.  I was afraid that I would get that response.  Regardless, is there a way to make an average of the averages?  Thank you.
Title: Re: How to make an Average of Averages- Thank you
Post by: Suraj on 20 Sep 2007 03:12:06 PM
Hmmm...
I'd first of all take the total of each % values such as for 97% it will be .97, for 98% it'll be .98 etc...
Then divide the total number by Count(departments or whatever is your criteria) to get the final number that can be formatted as %.

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I'm afraid not, the "total(completed orders for report)/total(projected orders for report)" is what I meant by "the summary average is 2729/ 2843 = 96% which is different than the average of 97%, 98%, 94%, 100%, 89%, 100%, 96%, 98%, 88%, 85% which is 95%".
Title: Re: How to make an Average of Averages- Thank you
Post by: JoelR on 21 Sep 2007 09:05:42 AM
Thank you for your response.  But what if a department is 0%?  I would not want to divide 10 departments by 10 if only 9 departments have averages greater than 0%?  Even if your suggestion would work would you then reference the  percentage field and then reformat the new field as a decimal?  Would your average calculation look like this? count(average of departments/# of departments)?
Title: Re: How to make an Average of Averages- Thank you
Post by: Suraj on 24 Sep 2007 11:35:18 AM
In that scenario, you have to create a data item that counts # of departments only if avg > 0.