I am in the process of negotiating a reduced hours/pay position with
my law firm and need to compile some data before formalizing an
agreement.  Information regarding the following would be very helpful:

1.  How much are benefits worth?  I am willing to give up my benefits
here (as I am insured elsewhere) and need to know a ballpark figure of
their worth.  The firm provides medical insurance (but not vision or
dental), life insurance ($50,000 policy, I believe), and short-term
disability.  These specifics may be immaterial for the purpose of the
research though.  I just need a rough estimate, if that is all that is
practical.  I believe I read once that an employee's benefits package
is worth approximately 7-12% or that person's salary, but I could be
wrong.

2.  Roughly, how much does attrition cost law firms?  This is a cost
they often do not consider, but the cost of training a new associate,
especially in a specialized field, is very high I'm sure.  For the
type of law I practice, it takes about 6 months to really be able to
contribute to the firm.

3.  What is a total cost of employment?  I've heard that a rule of
thumb is 10-20% of your salary.  I guess this number is related to
Question 1, in that it includes insurance, but also involves overhead,
administering the 401K program, etc.

This is all I can think of right now; I hope it makes sense.  If you
need more information, please ask.  Thanks!

Are you going to be engaged as an independent contractor or as simply
a part-time employee who will have no benefits in exchange for a
reduced salary?

Let's assume the latter, and further assume that if you were going to
be hired as a full time associate your annual salary (with benefits)
would be $100,000.  So, if you are going to work 20 hours per week and
have no benefits, a fair "translation" of the preceding assumptions
would bring your pay in at around $65,000.  Half-pay (for half-time),
plus a 15% kicker for foregoing benefits--this accords with your
estimate that the cost of employment is around 15-20% of salary.

Attrition is not a factor.  New associates are fungible--much of their
time is written off by partners anyway.