WASHINGTON (AP) _ The growth in information technology has been a major factor lifting the productivity of American workers, Federal Reserve Chairman Alan Greenspan said Tuesday.

``What differentiates this period from other periods in our history is the extraordinary role played by information and communication technologies,'' Greenspan said. ``The effect of these technologies could rival and arguably even surpass the impact the telegraph had prior to, and just after, the Civil War.''

Greenspan used his remarks before the New York Association for Business Economics to try to bolster the case that a significant rebound in productivity _ the output per hour of work _ has occurred in recent years and that much of the improvement was due to basic changes in the economy, rather than temporary factors that could disappear.

``Our economy is benefiting from structural gains in productivity that have been driven by a remarkable wave of technological innovation,'' Greenspan said in the speech, which he delivered by satellite hookup to the conference in New York.