Starting with today's editions, The Washington Post is expanding its statistical measurement of stock market activity with the addition of two indices. These tables will be published every day as part of the market indicators, which are printed with the first page of New York Stock Exchange quotations.

To provide a daily barometer of major Washington-area corporations, The Post will publish the indexof 30 stocks developed by the investment firm of Johnston, Lemon & Co. Inc. Since the mid-1970s, this index has been a weekly fixture of The Post's Business & Finance section on Sunday, and the weekly index will continue to be published there.

A much broader index of all stock market activity every day has been developed by a California investment services firm, Wilshire Associates. The Wilshire 5000 Equity Index includes all New York and American exchange issues and virtually all over-the-counter securities. The Wilshire Index was developed in 1975 by Wilshire President Dennis Tito.

Tito's index has gained a growing following in the investment community. He said this is because it is a better tool to measure performance of investment managers than such popular barometers as the Dow Jones average of 30 industrial NYSE stocks and the Standard & Poor's 500-stock index. When the Dow was started, it represented a large portion of all market capital. Now it represents primarily "mature" companies that represent less than 17 percent of market capital.