Why is the formula not the other way around, please elaborate

of workers seeking a job is U + sN + NZ. The chance that a job seeker finds a job is the number of job openings divided by the number of job seekers: Ns + NZf U + Ns + NZ If we multiply by (U + sN + NZ) on both sides and multiply f into the parenthesis we see that the term N . Z . f cancels out and we get fu + fNs = Ns. Thus we get Ns f = U + Ns The share Z disappeared from the expression because every employed worker who switches jobs leaves one job opening and takes another. Turnover between jobs does not leave any job openings for unemployed workers. The expression for fcan be approximated as follows: Ns S S S U + Ns LI + S UL +S N LN u +s