Assigning numerical values to items in a list and generating a sum

Hello,

I am trying to create an intelligent staffing sheet for my hospital unit for nursing staff. This gets a little confusing...

I began by creating a drop down list with all of the possible shifts that each staff member could work. The unit is based around three shifts, Day (8am-4pm), Evening (4pm-12am), and Night (12am-8am). However, there are a number of varying shifts that each member can work which are either full or half shifts.

AM 8hr (8a-4p)
AM 12hr (8a-8p)
EVE 8hr (4p-12a)
PM 12hr (8p-8a)
PM 8hr (12a-8a)
AM Double (8a-12a)
PM Double (12a-4p)

What I want to do is assign a numerical value to each shift. For instance, AM 8hr contributes 1 to the staffing total for day shift but 0 for evening and night. AM 12hr contributes 1 to the day shift and 0.5 to the evening and 0 to night, etc.

Ultimately, I would have each staff member's name and every day of the week with a pull down menu where I could select a shift and a total for each day which is added from the values from the pull down menu. I want to have something that looks a little like this:

__A__________|B

1|_Gary_______|AM 8hr
2|_Carol_______|AM 12hr
3|_Betsy______|AM 8hr
4|_Bridget_____ |EVE 8hr
5|
6|_Total Day___|3
7|_Total Eve___|1.5
8|_Total Night__|0


Where the totals for each shift are generated automatically.

Any thoughts?