This paper considers anew the simultaneity problem that arises when observations of transactions are used to study the demand behavior of price- taking consumers.
Simultaneity is shown to be a problem of censored outcomes.
This fact is used to obtain a basic negative finding on identification in the absence of prior information on the structure of demand or the process of price determination. Then the assumption of downward sloping demand is imposed. The main result of the paper is a proposition showing that this assumption has considerable identifying power. An empirical illustration is provided. If you experience problems downloading a file check if you have the proper application to view it first.