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Investigate the role of parcel_sizes settings in proforma #160

Open hanase opened 5 years ago

hanase commented 5 years ago

The yaml file of the feasibility model sets parcel_sizes to 10000. It says here that the value does not matter because it cancels out in the pro-forma computation. Is that true? How do the forms change if we change this value?

hanase commented 5 years ago

Various proforma values are computed "per sqft", so for those it does not matter. However, the parcel_sizes constant influences the construction time which influences the profit. It should be computed on the actual parcel sizes. Or, does it matter if construction time for all parcels was computed with the same value and thus, influences all proposals the same way?

hanase commented 5 years ago

The settings of parcel_sizes does matter in terms of the profit comparisons between parcels. The picture below compares profits for parcels in the tcu form. The profit computed with parcel_sizes of 10,000 is on the x axis, while profit for parcel_sizes of 20,000 is on the y axis. Each dot is one parcel. In the profit computation, the building revenue is the same for both settings, but the total development cost differs because the construction time differs. The max profit difference for this form is 390,005.

profit_parcel_sizes_tcu