1. In a computer-implemented financial trading system, a method for automatically generating a securities transaction assessment to participants of the financial trading system, comprising: receiving, by a computer, historical transaction data for a plurality of executed securities transactions over an electronic data network, wherein said historical transaction data includes, for each executed securities transaction, a data element that identifies one or more parties to said transaction; receiving, by said computer, data identifying a set of one or more possible index fund transactions, said data including, for each of said possible transactions, one or more of the following data elements: a security name or identification symbol of the index fund, a value or price associated with said possible transaction, a type of said possible transaction, and an identification of a party associated with said possible transaction; determining, by said computer, a set of relevant executed securities transactions from said plurality of executed securities transactions, wherein the relevance of an executed securities transaction is based on its membership in the set of securities that form the index of one or more of said possible transactions; calculating, by said computer, for each relevant executed securities transaction of said set of relevant executed securities transactions, a degree of similarity of the executed securities transaction to the one or more possible transactions, wherein the degree of similarity is based upon a plurality of predetermined variables; generating, by said computer, an assessment of said one or more possible transactions based on the historical transaction data of said set of relevant executed securities transactions, wherein the generation of said assessment includes the weighting of each relevant executed securities transaction based on a level of expertise of the identified party associated with the relevant executed securities transaction and the calculated degree of similarity of the executed securities transaction to the one or more possible transactions, and aggregating the weighted data; and generating, by said computer, a certainty indicator for the assessment, wherein the certainty indicator indicates a probability that the assessment would meet a participant's stated objectives.