date difference in same column (multiple dates)

[alevandenes]

Hi all,

I want to calculate the Mean time between failures for some machines (average number of days between one failure and the next one for each machine)

I have one column with all the machine numbers and one column with the notification dates.

DATEDIFF doesnt work because i am comparing data in the same column and not in different ones.

Anyone has a suggestion on how to solve this? I thought about pivoting/unpivoting but i cant seem to get it right.

I found in this forum a solution, but it applies only in cases i have two dates

Date Difference = CALCULATE(DATEDIFF(MIN(Table1[Max Date]), MAX(Table1[Max Date]), DAY), ALLEXCEPT(Table1, Table1[Name]))

Ideas?

Thank you in advance,
Alessandra

[Greg_Deckler · Accepted solution]

@alevandenes - I have an article on MTBF - See my article on Mean Time Between Failure (MTBF) which uses EARLIER: http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/3395....
The basic pattern is:
Column = 
  VAR __Current = [Value]
  VAR __PreviousDate = MAXX(FILTER('Table','Table'[Date] < EARLIER('Table'[Date])),[Date])

  VAR __Previous = MAXX(FILTER('Table',[Date]=__PreviousDate),[Value])
RETURN
  __Current - __Previous

[alevandenes]

Hi @Greg_Deckler 

I was wondering if you had a solution also to exclude non-working hours from the calculation of Repair Hours?

Your article helped incredibly.

Kind regards,

Alessandra

[alevandenes]

Wow thank you very much!! The article is great

[amitchandak]

@alevandenes , I think You need to try like

last Actual start date = maxx(filter(Table, [Equipment] = earlier([Equipment]) && [Actual start date] <earlier([Actual start date])),[Actual start date])