It's very important index values are unique, if you have similar Dates Received I would suggest you bring additional field into the model to create unique Index along with current field (like a composite unique key) or create the index on the data source side.
Once Index is created, let's create second Index only for Active values
I have finally had chance to try it out, but unfortunately it hasn't quite worked for me. All of the columns and measures appears to go through without a problem but when I create the graph as suggested I just get each month with the same number of 'active'.
Also, lookint at your example i'm not sure it is really showing what I am after. what I would like to see if the number of applications that WERE active in January. what I think your graph shows is the number of applications received in January that are still active.
So your graph should display 7 for Janaury and 12 for February [4 received none ended] but then 15 for March [4 received by 1 ended]
Thank you again, but not sure i'm going to achieve what I want to without adding in loads of columns. I was thining I could add a column for each month and to calculate the 'active' based on the dates, maybe I can do this as a sepeteate table though?
So if I'm reading your post right, you're wanting for, say, January, anything that has a received date in January or earlier, but at that time no end date? If that's the case, then it's equivalent to something having either no end date, or an end date in February or later, so you could try making calculated columns that converts both dates into year-month format (i.e. this month is 201710), converts your blanks in the end date to some large number, do the same on your date table, then do some calculation where for anything in your date table, it counts the number of rows where the received date is <= the date table value, but the end date is > the date table value