Today's American economy is less sensitive than ever to political change, Sumner H. Slichter, Lamont University Professor, said yesterday.

In an article in the New York Times Magazine, Slichter said the recent growth of the economic structure is "reducing the differences between the political parties and are making quick and drastic shifts in public policy quite unlikely."

Slichter outlined four reasons for this economic development: (1) the growth of built-in stabilizers; (2) the improvement in the art of business management; (3) the rapid growth of the new "industry of discovery," and (4) the great improvement in the position of consumers.

Under the first heading, Slichter included such things as pension plans, unemployment compensation, and the large expenditures by federal, state, and local governments.

Discussing the improvement in business management, Slichter said "the progress achieved in the last 25 years has been particularly impressive."

One result of this improvement, he continued, "consists in the fact that today's decisions are to a growing extent being affected by long-range considerations and that the uncertainties of the moment and other short-run matters have less influence than they once had on the decisions of executives."

The rise of the "industry of discovery"--by private and government institutions--makes the economy "less sensitive to political changes and political uncertainties for the simple reason that it enormously increases the influence of technological change and prospective technological change upon the policy decisions of business," he said.

Slichter showed with statistics that the American consumer is better off now than in the past, and has shown confidence in the economy, even when his income has fallen