Why the formula is like, i think the number of job openings is at the denominator? why is it not?

o How many workers are seeking a job? The workers seeking work consist of the workers unemployed at the beginning of the month. U, plus those who quit exogenously, N - 3, plus those searching on the job, N - Z. Thus, the total number of workers seeking a job is U + 3N + NZ. _ Air + NZf ' u + N: + N2' if we multiply by (U + W + NZ J on both sides and multiply f into the parenthesis we see that the terrnN-Z~f cancels outand we geth+st=Ns. Thus we get Mr I = 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 f can be approximated as follows: I Ns s s s = ==-ER$ , f U+Ns +s Eff-H u+s where u is the unemployment rate U /L. This approximation holds because UN is a number close to unity. We use the approximation because it is intuitive and easy to remember. The chance of getting a job is equal to the share of jobs being left by those who leave their jobs for exogenous reasons divided by the share of job seekers - that is, the unemployed plus those who leave their jobs for exogenous reasons. The chance of getting a job decreases if unemploy- ment increases and increases if there is higher turnover. if, for example, 5 is 2 percent and u is 6 percent, the chance of getting a job within a month is approximately 25 percent (0.02/ {0.02 + 0.06)). If, instead, 5 is 1 percent and u is 9 percent, the chance of nding a job within a month is only about 10 percent rnm Ham 4. nm 11