Growth rate of the firm

The ability of a firm to grow is determined by the number of partners and associates the firm has to do the work. The growth can be represented by the following formula:
g = rp - ap + sl
rp is the recruitment rate of partners.
ap is the attrition rate of partners.
s is the fraction of associates who made partner (a to p).
l is the ratio of associates to partners (a over p).
(via pdb)