Calculating a difference Overtime

[LewisH]

I Have 2 Measures named 'Request' and 'Resolved'. These Values are linked to a datekey so I can view the values for every month. 

I want a new measure which will record the difference between these values Each month. In the below picture for example I would expect to see 

        | Request | Resolved | New Measure 

April |       78            43                  35

May  |     139          119                 55

June |       41            46                  50

The calcualtion is New Measure =  Request - Resolved + New Measure(Previous Month)

I tried something like this but it was very far from working

measure = calculate([request]-[resolved], filter(all(DateKey), DateKey[Date] <= max(DateKey[Date])))

[v-ljerr-msft]

Hi @LewisH,

If I understand you correctly, the formula below should work in your scenario. 

New Measure =
[request] - [resolved]
    + CALCULATE ( [request] - [resolved], PREVIOUSMONTH ( Table1[datekey] ) )

Regards

[LewisH]

Thanks, However this doesn't seem to factor in the previous months values... It calculates the Requested - Resolved correctly, but no addition of the previous month

[v-ljerr-msft]

Hi @LewisH,

Could you post your table structures with some sample/dummy data, so that we can further assist on this issue? It's better to share a sample pbix file. You can upload it to OneDrive or Dropbox and post the link here. Do mask sensitive data before uploading. 

Regards