Logic to calculate average number of employees per day...

Question

Hi,
In an internal table, i have employee number, start date, end date.
This table shows employee's start and end dates for a cost center.
Now, the requirement is to calculate the average number of employees available per day for a given period...
Lets asume that we would like to calculate average number of employees per day for a given period of 30 days (01.01..2009 to 30.01.2009)....
The above table will have around 20 employees with their start and end date.
Among these 20, some may be present between 1st to 10th Jan only..
In such case, How to calculate average number of employees per day in such case?
Can anyone help me out with a rough sketch of logic for this calculation?
Thanks in Advance,
Pavan

Answer 1

My Logic:
1) First choose dates from which date to which date you are planning to calculate. [Here i am trying to calculate from Jan 1st 2008 to till date - March 3rd 2009 = So total days = 427 days]
2) First try to count number of days worked in organization by each employee. [Lets take employee a = 10 days, b = 182 days, c = 427 days].
3) Then total all the number of days. [abc = 10182427 = 619 days].
4) Total number days / Total number of days worked = 619 / 427 =  1.44 employees per day.
Employee     Emp-Start Date     Emp-End Date     No. of days
a             Jan 1st 2008     Jan 10th 2008     10
b             Jun 1st 2008     Jun 30th 2008     182
c            Jan 1st  2008     3rd March 2009     427
          Total No. of days                     619
     From Jan1st 2008 to Till date 3rd March 09          427
          619 / 427 =     1.449648712
I tried take simple example to recheck the above scenario is correct or not. If 'n' number of employees worked for an organization in a year (365 days) is 730. then per day = 730 / 365 = 2 employees per day worked for organization.
I am not sure my logic is correct or not ... just tried like above.
Regards,
~Satya