Using two data sets from the same source but in different years (1994 and 1997) and regions (Northeast and Southeast), benefit transfer estimates are compared with original estimates to examine the convergent validity of benefit function transfer. Although benefit transfer error could go up to over 400% of original estimates for a particular case, the magnitude of benefit transfer error is less than 100% of original estimates for most cases. Since two data sets used for benefit transfer are from different regions and years, whether regional or temporal variation is more responsible for benefit transfer error can not be determined without intra-regional or intra-temporal data.