Dear All,
As per me there should be 3 types of attrition calculation methods :
1) Monthly Attrition : To understand specific month status
= ( separation in the month) / ( openg of mth + closg of mth)/2
2) Year till date attrition : to know YTD status
= similarly like above but period has to be proper like if i said for the period apr 09 to dec 09 then opng should be of Apr 09 and clsg should be of Dec 09
3) Annual Attrition : This will help us to keep an eye on the attrition trend and take appropriate measures in time. This helps us as a forecasting tool.
= (total no. of separations) / (avg of opng balances) / no. of mths considered for calculation * 12
e.g. If we want to know the attrition trend in the year 2009 and we are in apr 09, it will work as follows:
Jan 09 : opg - 120, Left - 5
Feb 09 : Opg - 115, Left - 7
Mar 09 : Opg - 121, left - 6
Apr 09 : Opg - 123, left - 3
then our annual attrition will be = (5+7+6=3)/ ( avg of (120+115+121+123))/4 * 12
This will tell us our status in the year end if we continue to loose the people in last 4 mths.
Hope this will help all of us.
Bye