Benefit transfer tools
The package includes the following tools, which could be useful for benefit transfer:
Transfer Error Matrix
Calculate relative transfer errors (element-wise operation to two arrays with implicit expansion enabled), according to:
TE = (WTP_transferred - WTP_observed) / WTP_observed
where transfered values can be income adjusted, according to a specified (fixed) income elasticity:
WTP_transferred = WTP_study*(INC_transferred_country/INC_study_country)^elasticity
Minimum Tolerance Level
The function finds a Minimum Tolerance Level (error rate) that allows for the conclusion that two empirical distributions (distributions of WTP or measures of WTP that are estimated with uncertainty) are 'equivalent' at the 5% significance level. This could be particularly useful for Benefit Transfer (Czajkowski and Ščasný, 2010; Czajkowski et al. 2017).
Equivalence is defined in accordance with Kristofersson and Navrud (2005). The optimization uses Two One Sided Z tests (TOSZ, for normally distributed random variables) or Two One Sided Convolutions tests (TOSC, for all other distributions). The convolutions approach is described by Poe, Giraud and Loomis (2005).
Minimum Tolerance Level Matrix
Calculate Minimum Tolerance Levels (element-wise operation to two arrays with implicit expansion enabled), where transfered values can be income adjusted, according to a specified (fixed) income elasticity:
WTP_transferred = WTP_study*(INC_transferred_country/INC_study_country)^elasticity
