<DIV>More than half a decade has passed since the bursting of the housing bubble and the collapse of Lehman Brothers. In retrospect, what is surprising is that these events and their consequences came as such a surprise. What was it that prevented most of the world from recognizing the impending...</div>

<DIV><DIV><P>            Quantitative measures of international exchange have historically focused on trade in tangible products or capital. However, services have recently become a larger portion of developed economies and international trade, and will only increase in the future. In...</i></p></div></div>

We define a class of bias problems that arise when purchasers shift their expenditures among sellers charging different prices for units of precisely defined and interchangeable product items that are nevertheless regarded as different for the purposes of price measurement. For...