“The human factor†in the history of changes in the Dow Jones Index lists

In the scientific literature devoted to the study of stock markets, the issue of changes to the lists of indices studied in many works, however, in the vast majority of cases they studied only the consequences of including a stock in the list of stock indices - or of their exclusion from such lists - from the point of view of change of quotations of this stock, the volatility of these changes, sales volume and other similar characteristics. At the same time, there are no publications which have addressed the question of why the shares of this company included in the index list, and some other company are excluded from this list, and, most importantly, how appropriate for this time period was the change. This issue, i.e. assessing the level of correctness of the decisions taken by the leadership of the stock index when you change its list, and which is called here «human factor» are the focus of this article. The results based on the analysis of the lists changes in the index Dow Jones for more than 120 years the story of his calculus. It is shown that this factor has a significant impact not only on the qualitative composition of the lists of the index, but also on the dynamics of its values, as accelerating growth and slowing it down. On the basis of statistical data about the frequency and intensity of replacements of companies in the lists of the index is evaluated the quality of the US stock market in different periods of time from the point of view of stability of its composition and the volatility of trading.