Running total per period

Hello Shockedrope ,

Try this:

Create a calculated calendar table like below:

Dates = 
ADDCOLUMNS (
    CALENDAR ( DATE ( 2015, 1, 1 ), TODAY () ),
    "YYYYMM", FORMAT ( [Date], "YYYYMM" ),
    "Year", YEAR ( [Date] ),
    "Month Name", FORMAT ( [Date], "MMMM" ),
    "Month Number", MONTH ( [Date] )
)

Create a relationship single direction one-to-many relationship between Open Date from your fact and the Date from the calculated table.

Create this measure 

Open Tickets =
CALCULATE (
    //count of tickets
    COUNTA ( 'Table'[Ticket Name] ),
    //filter tickets opened on or before the max date in the current context
    FILTER (
        ALL ( Dates ),
        Dates[Date] <= MAX ( Dates[Date] )
    ),
    //from the filter above, filter tickets without or with future closed dates
    FILTER (
        ALL ( 'Table'[Closed Date] ),
        'Table'[Closed Date]
            > MAX ( Dates[Date] || ISBLANK ( 'Table'[Closed Date] ) )
    )
)

Add YRMO column from the Dates table and Open Tickets Measure to a table visual to test the formula.

Download the sample pbix from here: https://drive.google.com/file/d/1tqLK-aPakHWxxAKr0UwxA2bQjll-gO1T/view?usp=sharing

Shockedrope 

Create a new calculated column as below.

Open? = IF(ISBLANK(Table[Closed Date]),1,0)

The join the table with date dimension(below) based on Open date.

Calendar = CALENDAR(MIN(Table[Open Date]),MAX(Table[Closed Date]))

Create a visual with month from date dimension and measure from the table

Cumulative sum = CALCULATE(SUM(Table[Open?]),FILTER(ALL(Table[Open Date]),Table[Open Date]<=MAX(Table[Open Date])))

If it helps, mark it as a solution

Kudos are nice too

If you use a month as a period. Does that define an open ticket as one what was opened before the month, or during the month, but still had not closed by the end of the month ? What if you use a week as a period ? Is the logic the same, but with weeks?
So your count of "open" may vary depending on the time period.

What you have is what they call a "slowly changing dimension"... your service record changes over time and when you want to report on it all you have available is the current version.

One possibility is to take snapshots. Decide on a reporting period. Record a data table of tickets that are open at the end of each period and how many days they have been open.

Then you could write reports against that table.

Power BI is easy to learn, but it has hard parts. I'm a personal Power Bi Trainer I learn something every time I answer a question

Hi,

If you want a running total by month, then i can help.  Also, do you want a running total since inception or should the counter reset at the start of each year?

Thank you for the suggestions. I was able to find my solution by following this article: https://community.powerbi.com/t5/Community-Blog/HR-Analytics-Active-Employee-Hire-and-Termination-trend/ba-p/882970