Subtract Single Measure Used in Two Columns in Matrix

[Anonymous]

Greetings,

I'm struggling to get my head around how to substract a measure that is used twice in my matrix. Below is the table:

Forecast Type	Week Ahead	Two Weeks Ahead
Node Type	Accuracy	Accuracy
Gen 1	100%	98%
Gen 2	20%	15%
Gen 3	95%	93%

I have a single measure that calculates the accuracy across my Forecast table, how would I substract the Accuracy from the Week Ahead by the Two Weeks Ahead?

My desired result is the following:

Forecast Type	Week Ahead	Two Weeks Ahead
Node Type	Accuracy	Accuracy	Accuracy Difference
Gen 1	100%	98%	2%
Gen 2	20%	15%	5%
Gen 3	95%	93%	2%

Any help would be greatly appreciated as my head is fried looking at this 🙂

[Anonymous · Accepted solution]

I got around it by doing two CALCULATES, filtering by the Forecast Type and then subtracting one from the other, not 100% what I was after but filled a gap 🙂

[Anonymous]

@amitchandak Thanks for yo're reply. This does not involve dates, the Accuracy measure averages the half hourly accuracy calculation from the table across a couple of forecast types (week ahead and two weeks ahead), I am presenting to the users a comparsion of a summary of the accuracy percentages, I'm trying to substract the accuracy from the week ahead vs the two week ahead, no date data is used. 

The data is complicated as it's using direct query to pull the data across a number of tables. Does the above help at all?

[V-lianl-msft]

As I don't know your data model, it's difficult to give accurate suggestions. If you want to calculate Two Weeks Ahead measure, you need to take the date field as the filter condition. If Two Weeks Ahead is an existing column, you  need to use the aggregate function to convert the column into a measure.

[amitchandak]

@Anonymous , do you week in date or week format ?

Can you share sample data and sample output in table format?

Refer Power BI — Week on Week and WTD
https://medium.com/@amitchandak.1978/power-bi-wtd-questions-time-intelligence-4-5-98c30fab69d3
https://community.powerbi.com/t5/Community-Blog/Week-Is-Not-So-Weak-WTD-Last-WTD-and-This-Week-vs-Last-Week/ba-p/1051123
https://www.youtube.com/watch?v=pnAesWxYgJ8