I have looked at the paper and the Pakistani data here:
http://www.census.gov.pk/Statistics.php
http://data.worldbank.org/country/pakistan#cp_wdi
http://www.pbs.gov.pk/
It appears that they have consumption data as well as percentages for population statistics. The only thing that I could not find was wage data. I would take the tax rate, debt and interest rate as given. What might be best is to use a model similar to Klein and Goldberger (1955) and use 2sls or 3sls to estimate the magnitudes of the of the coefficients.
With that I would then see how different the regression results are for equations 1 and 2 in the paper, if they are different I would the calibrate the models to equate the two by adjusting the q variable (amount of goods invested in child) to make the models match using solver in excel. I would think this should work as this is the one variable that would be difficult to measure. If we assume the model to be correct it could be interesting to see how sensitive human capital is to this. This would also allow you to get back to the CRRA utility that Zhang starts off with. I would also probably do a few countries for comparision since there was no empirical testing in the paper just to see how the numbers compare.
This is an interesting topic, I would be interested in helping, the biggest issue I see at the moment is finding some wage data that would span the consumption data from 1960 - present. Since I am not up on the Pakistani macro data perhaps you know of a source for which I am unaware.
I'm not sure that would be a good idea as there may be a divergence between wages earned and the income per capita. I am trying to back my way into it, if I use the data from 1960-1999, before they changed the accounting base I get the following in a 3SLS model:
C = constant + b1(GNP) + b2(C(t-1))
I = constant + b1(GNP(t)-GNP(t-1))
GNP = b1C + b2I + b3NX
they actually include government spending in net exports so the system should still be robust.
Equation system, 3slswithNX
Estimator: Three-Stage Least Squares
Equation 1: 3SLS, using observations 1961-1999 (T = 39)
Mean dependent var 337158.8 S.D. dependent var 192532.1
Sum squared resid 1.57e+11 S.E. of regression 63486.72
At the moment this seems fairly robust, but I am going to play with it a little more. This would mean the MPC is .87 resulting in a multiplier of around 7.5, so Pakistan is pretty dependent on consumption, which should eventually effect the choices of children and education. What I want to do is see if I can work back now from the Aggregates to the Solow/New growth theory stuff so that we can develop a metric to calibrate the agent model to the Macro statistics.
Let me know if this triggers any ideas, I will be playing around with this next week and see where I get.
calibration mean that you have built a theoretical model, but its empirical has already done earlier.
if you see Romer's book then you simply find out that many a time in the start of the chapter of he discuss the model, then later on he puts value from different empirical.