Field Information - Subset ratio

[Anonymous]

Hello everyone,

I am completely new to QlikView and I am reading the book titled QlikView 11 for Developers. On page 106 of this book, I came upon a definition of Subset ratio which goes as follows:

Subset ratio, which shows the percentage of all distinct values for a field in

the table compared to all the distinct values for that field in the entire data

model. It is only relevant for key fields since they are present in multiple

tables and do not all share the same value. Subset ratios can be used to easily

spot problems in key field associations. For example, when the combined

total of subset ratios for multiple tables is 100 percent, this may indicate that

there are no matching keys between these tables.

Please, I need someone to break the above definition down for me.  I do not understand it very well.

Thanks.

[trdandamudi]

Check for Information Density and Subset Ratio

• Information density indicates the percentage of rows that contain a distinct value for a field.
• Subset ratio (only on key) shows the percentage of all distinct values for a field in the table compared to all the distinct values for that field in the entire data model.

Both indicators are paramount when verifying the data model. They indicate if the key chosen is a quality field between 2 tables. If there are no/little common values between the 2 tables, it means that the key cannot be used or that the key is not precise enough. It saves a lot of time and can be used to check a key before joining 2 tables.

https://www.element61.be/en/resource/professional-testing-qlik-application

What is the difference between Subset ratio and information density.

Hope this helps..

[pooja_prabhu_n]

Hi,

Refer this link for more information.

information density and subset ratio? What is the use of this?

Thanks,

Pooja

[arvind1494]

• Information density: This displays the percentage of rows in the table with values (none are null).

• Subset ratio: This displays the percentage of distinct values in this table for this data field (out of all possible distinct values for the data field contained in all tables).

[Anonymous]

Thanks everyone.  The links and comments were very helpful.  I have a better understanding of Subset ratio now.