For owner farmers, potential taxable income (PTI) is calculated by subtracting an estimate of COP from GVO. Following Khan and Khan (1998) and World Bank (1999), we have taken COP to be 40 percent of GVO.
We calculate GVO for farms classified as irrigated and unirrigated, and estimate tax potential for both types of farms separately using a methodology very similar to the one described in the preceding subsection [see Nasim (2012) for details].
(21) Khan and Khan (1998) mention that COP varies between 35 and 45 percent of GVO. World Bank (1999) also report that several farm management studies in Pakistan support the assumption that COP per acre varies between 35 to 45 percent of GVO.
VA = (GVO - [COP.sub.unAdj]) = GVO - [lambda]GVO = (1 - [lambda]) x GVO