weighting factor in bridge table

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weighting factor in bridge table

Post  revdpoel on Fri Aug 26, 2011 5:25 pm



Hai

in the added model I understand the use of a bridge table. But I keep on having trouble understanding the use of a 'weighting factor'.. Can someone explain me in a simple and clear way the use of this attribute in this example?

Thanks
Ron

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Re: weighting factor in bridge table

Post  ngalemmo on Sat Aug 27, 2011 2:16 am

Weighting factors are used to allocate measures when are multiple targets. Using your model, if the account maps to multiple customers and you wanted to report account snapshots by customer, you would use the weights to porportion measures (such as interest paid) across the customers holding the same account.
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A little example

Post  gerardnico on Sat Aug 27, 2011 3:47 am

Just to add a little report example at this many to many problem.

Without Customer:
Account Number of Transactions
100000 100
Total 100

With the customer:
Customer Account Number of Transactions
The customer 1 100000 100
The customer 2 100000 100
Total 100000 200
As you can see the total is not good, you have to correct it with the weighing factor:

With the weighing factor:
Customer Account Number of Transactions Weighing factor Number of Transactions Corrected
The customer 1 100000 100 70% 70% x 100 = 70
The customer 2 100000 100 30% 30% x 100 = 30
Total 100000 200 50% 100


Last edited by gerardnico on Sat Aug 27, 2011 4:04 am; edited 1 time in total
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Re: weighting factor in bridge table

Post  revdpoel on Sat Aug 27, 2011 3:54 am

Thanks ngalemmo

and what then is, in my example, the difference between impact and weighted report?

Thnx
Ron

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Re: weighting factor in bridge table

Post  revdpoel on Sat Aug 27, 2011 3:56 am

gerardnico wrote:
Account Number of Transactions
100000 100

Customer Account Number of Transactions
The customer 1 100000 100
The customer 2 100000 100

Hello, gerardnico, thanks for the reply but I don't know what you are trying to say with this.

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Bad button

Post  gerardnico on Sat Aug 27, 2011 4:06 am

Hello,

I was struggling with the table and I have pushed the Send button in place of the preview. I have just modified my previous ticket with the complete example.

Cheers
Nico
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Re: weighting factor in bridge table

Post  revdpoel on Sat Aug 27, 2011 4:18 am

gerardnico wrote:Hello,

I was struggling with the table and I have pushed the Send button in place of the preview. I have just modified my previous ticket with the complete example.

Cheers
Nico

Thanks Nico for the example
clear
In the bridge table you have foreign keys of customers and accounts, with their weighting factor
Wehere do I fit in your customer called 'Total' with weighting factor 50%? I mean, do I have to insert a customer called 'Total' then in the customer dimension?
And what is difference between impacted and weighted report?

thnks
Ron

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It's a report, I just have added a total line

Post  gerardnico on Sat Aug 27, 2011 4:36 am

The last line is a total that any report tools can make and doesn't come from your model.
- For account: a max
- For Number of Transactions: a sum
- For weighing factor: an average but as you do the sum, you must have 100%

I think that Impact report is the second example (Do you see the impact, a bad sum)
and weighed report the third (the corrected one)

Cheers
Nico


Last edited by gerardnico on Sun Aug 28, 2011 6:33 am; edited 1 time in total
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Re: weighting factor in bridge table

Post  revdpoel on Sun Aug 28, 2011 6:29 am

Great, I understand
but the weighting factor is not an attribute you get from a source system
So how do you compute / determine the weihgting factor for each individual customer?

Ron

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Re: weighting factor in bridge table

Post  gerardnico on Sun Aug 28, 2011 6:37 am

The weighting factor is determined:
- of by the business
- of during the load with a calculation.

If you have for the same account:
- two customers, then 50% (100/2)
- three customers , then 33% (100/3)
- etc ...

Cheers
Nico


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Re: weighting factor in bridge table

Post  gerardnico on Sun Aug 28, 2011 6:41 am

I have forgotten, it can also be calculate by the reporting tool.
This kind of calculation during a report generation doesn't cost so much.
I work intensively with OBIEE and it's really easy to do as you just have to divide by the total of customer by account.

Cheers
Nico
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Re: weighting factor in bridge table

Post  revdpoel on Sun Aug 28, 2011 6:45 am

Ok Nico

but then it doesn't exactly reflect the reality then? It is, as to say indeed a weighted factor? It gives, let's say an indication

Ron

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Re: weighting factor in bridge table

Post  gerardnico on Sun Aug 28, 2011 9:32 am

In all cases, it reflects the reality of your data model. You affect proportionally the account metrics to your customers.

If when you say that it reflects not the reality because a transaction has always a customer, I will say that it's more a data modelling problem.

Cheers
Nico
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