An implicit rental price approach is used to analyse the determinants of farm tractor investment at the aggregate level. Three models, based on different assumed factor substitutabilities, are compared. Variations in the rental price of tractors appear to have less effect on demand than...

The fundamental assumption of the contingent valuation method (CYM) is that responses to CY questionnaires may be interpreted as expressions of consumer preferences. The consumer preference interpretation has been challenged in recent papers arguing that willingness to pay for wildlife...

It is shown that parameter estimates in a regression with a logarithmic time trend are not invariant to the choice of the starting point of that time trend. Possible solutions to this problem are discussed and applied to data from a recent article in this Review where a logarithmic time trend...