Delta method for RRM models
Posted: 07 Oct 2021, 20:39
Hi David and Stephane,
I have a question about the VTT error calculated from a RRM model. If I understood correctly the paper of Daly et al. (2012) about the computation of this measure, we calculate errors from a transformation of the parameters, and in the case of VTT is the ratio of the derivatives of the deterministic parcel of regret/utility in relation to time and cost attributes. In RRM models the VTT is not simply the ratio between the travel time and cost parameters (Chorus 2012 paper) of the alternative considered. My question then is: does it make sense to use the apollo function apollo_deltaMethod to calculate the error of this transformation for a RRM model? Or should I compute it manually? Thanks in advance.
Best,
I have a question about the VTT error calculated from a RRM model. If I understood correctly the paper of Daly et al. (2012) about the computation of this measure, we calculate errors from a transformation of the parameters, and in the case of VTT is the ratio of the derivatives of the deterministic parcel of regret/utility in relation to time and cost attributes. In RRM models the VTT is not simply the ratio between the travel time and cost parameters (Chorus 2012 paper) of the alternative considered. My question then is: does it make sense to use the apollo function apollo_deltaMethod to calculate the error of this transformation for a RRM model? Or should I compute it manually? Thanks in advance.
Best,