Fungibility and Consumer Choice: Evidence from Commodity Price Shocks*
研究利用汽油价格变动数据，检验消费者是否将汽油支出视为与其他收入可替代，发现价格上升时消费者转向低辛烷值汽油，且无法用收入效应解释，支持类别预算模型。
Abstract We formulate a test of the fungibility of money based on parallel shifts in the prices of different quality grades of a commodity. We embed the test in a discrete-choice model of product quality choice and estimate the model using panel microdata on gasoline purchases. We find that when gasoline prices rise, consumers substitute to lower octane gasoline, to an extent that cannot be explained by income effects. Across a wide range of specifications, we consistently reject the null hypothesis that households treat “gas money” as fungible with other income. We compare the empirical fit of three psychological models of decision making. A simple model of category budgeting fits the data well, with models of loss aversion and salience both capturing important features of the time series.