In the first stage, each person who is not already a shop owner (that is, has
another employer or is unemployed) becomes a potential entrant ("entrepreneur") with a
fixed probability =N, where the parameter represents the supply of entrepreneurship or
the weekly frequency of innovation. Each entrepreneur goes through the following process
to decide whether to enter.
First, the entrepreneur formulates a business plan for his prospective shop, which consists
of a wage rate w and a sales target ytrg. He sets the initial wage rate equal to the previous
week's (publicly known) economy-wide average wage, adjusted for expected in
ation over
the prospective wage contract period of weeks, where is a fixed parameter. He then
picks his sales target ytrg from a uniform distribution over [1; n] and plans to post the retail
price p = (1 + )w=(1 - ), which is a fixed percentage markup over after-tax marginal
cost.5 These choices imply a profit
flow II that the firm would earn if it opened and if its
sales target were realized.
Given this business plan, the entrepreneur will allow the opportunity for entry to lapse
if his financial wealth A (the sum of his money and bond holdings) is not enough to pay
for the fixed cost of operating the shop during the first month. He will also allow the entry
opportunity to lapse if his prospective profit II is less than his currently estimated permanent
income, which is discussed further below.
The entrepreneur also conducts "market research" before deciding whether to enter. In
particular, he sends invitations to two people, one a potential employee and the other a
potential customer, to form trading relationships with him if the shop opens. The potential
employee accepts if the shop's wage w exceeds his current "effective wage," and the potential
customer accepts if the shop's planned retail price p is less than his current "effective price."6
If either invitee declines, the entrepreneur allows the entry opportunity to lapse.
If he passes all these tests, the entrepreneur opens a shop with an "input target" equal
to xtrg = ytrg+F +I (ytrg - I), where I is the weekly inventory adjustment speed and I is
current inventories, which, for a new shop, are just equal to the entrant's legacy inventories.
Implicit in this equation is a desired inventory level equal to one week's sales.