How to get the latest flag based on multiple rows and only display this

[puzzle]

Hi there, I have an issue I am trying to resolve in my calculated column and am hoping someone can help?

Currently I am using a calculated DAX column to identify if someone is a new client based on if they have had a service in the last 6 months or not. It is working fine, however if someone has a new service, but then has a subsequent one afterwards then they are appearing twice as both new and existing.

What I would like to do is have this person in this scenario display as an existing client as they have had multiple services in the last 6 months. Example of what my table would currently look like below:

Person ID	New Client Flag
1	Y
2	N
2	Y
3	N
4	Y

This is the DAX I am using in my calculated column:

New Client? =

VAR pers = 'Appended Event Data'[Person ID]

VAR datetocompare = 'Appended Event Data'[Event start date]

VAR disregard = 180

VAR Prev_LT_serv =

CALCULATE(COUNTROWS('Appended Event Data'),

    FILTER('Appended Event Data','Appended Event Data'[Person ID]=pers),

    FILTER('Appended Event Data',AND('Appended Event Data'[Event end date]>=datetocompare-disregard,'Appended Event Data'[Event start date]<datetocompare)),

    FILTER('Appended Event Data','Appended Event Data'[Service Length] = "Long Term"))

RETURN

    IF ( Prev_LT_serv>0, "N", "Y" )

Any assistance is much appreciated, and thanks in advance!

[amitchandak]

@puzzle , refer the new customer logic

Period over Period Retention :https://community.powerbi.com/t5/Community-Blog/Customer-Retention-Part-2-Period-over-Period-Retenti...

CALCULATE(COUNTROWS('Appended Event Data'),

[puzzle]

@amitchandak 

Hi there, thanks for your reply.

I've given this a go, created 2 measures and a calculated column which doesn't seem to be working?

CLients accessing LT service = CALCULATE(COUNTROWS('Appended Event Data'),

                                FILTER('Appended Event Data','Appended Event Data'[Service Length] = "Long Term"))

LT Service within the last 6 months? = CALCULATE([CLients accessing LT service],DATESINPERIOD(Dates[Date],ENDOFMONTH(Dates[Date]),-6,MONTH))

New Client V2 = CALCULATE([LT Service within the last 6 months?] > 1)

Expecting to see anyone with more than 1 Long term service in the last 6 months appear as "True" and therefore not a new client, however everyone is returning as false.

Any ideas?