Hi @rsa_seun -
For NDR, I recommend reading this paper, written by one of our hydrologists, which includes sensitivity, uncertainty, and comparing with observed data:
Hamel, P., Guswa A.J. 2015. Uncertainty Analysis of the InVEST 3.0 Nutrient Model: Case Study of the Cape Fear Catchment, NC. Hydrology and Earth System Sciences Discussion 11:11001-11036. http://dx.doi.org/10.5194/hessd-11-11001-2014
SWY is harder, since only quickflow is quantified, baseflow is an index, and if you compare against stream gauge data, it will generally be a combination of both. The User Guide says this in the Limitations section:
One possibility is to validate the relative values (i.e. the distribution of values across the landscape). This requires several (at least >3, more realistically >5) stream gauges, which can be compared with the baseflow generation output of the model. Alternatively, results may be compared to a different spatially-explicit model, if it is available.
I’m only familiar with one NatCap study that did calibration on Habitat Quality, which you can read about in this paper:
Bhagabati, Nirmal K., Taylor Ricketts, Thomas Barano Siswa Sulistyawan, Marc Conte, Driss Ennaanay, Oki Hadian, Emily McKenzie, Nasser Olwero, Amy Rosenthal, Heather Tallis and Stacie Wolny. Biological Conservation 169:147-156.
Sorry, but I don’t know enough about the Crop Production model to help with that.