Filter on Measure in table

[QlikBeginner1]

Hello,

I have a table which users are able to select there own dimensions and measures. the app is a reconcilation app, and one of the fields is a match between two fields. The user is unable to filter to select 'not matching' instead of 'matching'. How can I add the filter option to the table.

the code being used is, If(round(Sum({$<TransactionPremSourceSystemName={'Acturis BE'}>}GrossWrittenPremium),0.01)
=
Round(Sum({$<TransactionPremSourceSystemName={'COGEN'}>}GrossWrittenPremium),0.01), 'Matching','Not Matching')

There is no filter option for the 'GWP Match' column.

thanks

[PrashantSangle]

try to create that field in backend.. then use it as dimension in front end