A beveridge curve show the relationship between unemployment and vacancy.
Some papers add additional variables like Real GDP, real interest rate, etc to test for the matching efficiency of the BC.
However when it comes to age structure. Some researchers use 1) Young Share in Unemployed, or 2) Young Share in labour force
What's the difference between 1) and 2)? How would a smaller young share in the unemployed vs the labour force affect the unemployment, vacancy and hence matching efficiency?