Can't we measure the growth in the income levels of poor? Inflation has been a challenging aspect 
of policymaking. In such situations growth in 
the income levels of the population living below 
the poverty level can never be measured 
accurately (due to higher infation poverty section will 
show higher income) . My question is: Due to higher inflation why cannot we measure growth in the income levels of the population living below poverty line accurately?
That's not specific to poor, any income increases with inflation.

The real problem is that the poor receive goods for free (charity, squatting, rent nonpayment) so their real income can never be measured.