Temporal stability of preferences and willingness to pay for natural areas in choice experiments: A test–retest

The main objective of this paper is to test the temporal stability of stated preferences and willingness to pay (WTP) values from a Choice Experiment (CE) in a test–retest. The same group of participants was asked the same choice tasks in an internet-based CE, conducted twice with a time interval of one year without interviewer interference. We examine choice consistency at individual choice task level and transferability of the underlying indirect utility function and associated WTP values. The results show that choices are consistent in 57 percent of the choice occasions. Comparison of the choice models over time shows that the estimated preference and scale parameters are significantly different, suggesting that choice behaviour changed between the two surveys. Differences between marginal WTP estimates for individual choice attributes are statistically significant only at the 10 percent level. However, we show that this can result in significantly different WTP values for policy scenarios. The instability of estimated mean WTP values for different policy scenarios asks for caution when including WTP values in cost-benefit analysis.     

Combining quality and quantity. A psychometric evaluation of the self-anchoring scale

In this study a psychometric comparison is made between a category rating scale with fixed anchors and a self-anchoring category rating scale where respondents themselves define the end anchors by referring to their personal experiences with the construct being measured. A student-satisfaction questionnaire was administered to 301 undergraduate students on two test moments separated by a 1-month period. Both types of category rating scales were crossed with both test moments according to a 2 ×  2 mixed factorial design. Our results show that respondents perceive the construct being measured in the same way with both rating scales. A comparison concerning different indicators of reliability, i.e. test–retest reliability, internal consistency and the error variances associated with each item, also failed to find a difference between both rating scales. In a last analysis it is demonstrated that using a self-anchoring rating scale or a rating scale with fixed anchors has a small but significant effect on the ratings of the respondents. In conclusion, a self anchoring scale may be the scale of choice if additional qualitative information from the anchors is warranted, but when quantitative comparisons between groups are required, rating scales with fixed anchors are preferable thanks to their ease of use.     

Test‐Retesting in Experimental Valuation of Perishable Food Products: Unstable Individual Bids and Reliable Market Demand

One important property of a preference measure is its reliability. In this article, we explore the reliability of experimental auctions in measuring the market demand for five types of fish. We use the test‐retest method to compare demand curves from two Becker–DeGroot–Marschak experiments with the same 116 participants conducted 7 months apart in time. The individual bids are not stable for these perishable products, but the distributions of the individual bids are stable. We find that the unsystematic individual variations cancel out in the aggregation of bids in a typical sample size for experimental valuation studies. Our results suggest that experimental auctions provide reliable market demand estimates even though the individual bids may change substantially over time.     

A within‐sample investigation of test–retest reliability in choice experiment surveys with real economic incentives

In this paper, we investigate the level of agreement between respondents' choices in identical choice sets in a test–retest choice experiment for a market good with real economic incentives, thus investigating whether the incentivised CE method can be reliable and stable over time. Besides comparing choices, we also test for differences in preferences and error variance when a sample of respondents is given the exact same questionnaire twice, with a time lag of 2 weeks in between. Finally, we examine potential reasons and covariates explaining the level of agreement in choices across the 2 weeks. Across four different tests, we find very good agreement between the two choice experiments – both with respect to overall choices and with respect to preferences. Furthermore, error variances do not differ significantly between the two surveys. The results also show that the larger the utility difference in a choice task, the larger the probability that the respondent will choose the same alternative in the retest. Moreover, the results show that the longer time respondents take to answer the 12 choice sets in the retest, the lower the probability that the respondent will choose the same alternatives in the retest as they did in the test.     

出口与企业生产率:基于中国经验的再思考

出口到底给中国企业生产率带来何种作用效应,既有文献的结论存在诸多矛盾之处。在着重考虑已有文献并未考虑到的企业TFP测算方法、企业进口以及出口贸易方式这3个方面因素的基础上,本文重新检验出口对中国企业生产率的作用效应,结果发现:除了纯加工贸易类型企业外,中国制造业企业的出口行为仍呈现自我选择效应;从新进入出口市场企业的角度来看,中国企业的出口活动中存在显著的"出口中学习"效应,这为出口对中国企业生产率所具有的促进效应提供了支持证据;从出口密集度的角度来看,企业的出口活动中存在"生产率损失"或"生产率抑制"效应,这又反映出口对中国企业生产率可能具有的负面效应。本文的检验结果及其解释,为理解出口对中国企业生产率的作用效应、判断出口对中国经济发展的综合作用效应提供了更为合理的微观经验证据。