Given the estimated parameters together with the data about current service level experienced by shippers as reported in Table 7, the elasticities of the utility relative to a percentage change in individual attribute levels were computed. A higher value of elasticity associated with an attribute means shippers are more sensitive to that attribute in selecting trucking services, implying greater priority being given to the attribute. The attributes were finally ranked according to the relative performance as reported in Table 9.
These conjoint analysis results revealed that both groups of shippers placed the highest importance on "reliability of on-time delivery". This result agreed with our earlier findings via the direct questioning survey and with similar studies completed elsewhere (i.e. Farahbod The second most important service attribute was the cost of trucking service. This observation differed from what we had discovered earlier in the second stage that shippers placed higher concerns on the damage and loss over price. The discrepancy in the findings between two survey techniques confirms our earlier critique of the direct questioning method that the respondents have an inclination to overstate the importance of certain attributes in the direct questioning survey because they generally assume better service can be obtained at no additional cost. When being forced to make a trade-off between improved service and higher cost during the conjoint experiments, shippers
would then respond more sensibly by giving serious concerns to the cost of service