# Worldwide Use and Impact of the NASA Astrophysics Data System Digital Library

## TL;DR

This paper analyzes the global usage and impact of the NASA Astrophysics Data System, developing bibliometric models and measuring its influence on astronomical research productivity and value.

## Contribution

It introduces Second Order Bibliometric Operators for improved literature searches and models worldwide research activity based on economic and demographic data.

## Key findings

- ADS impact in 2002 equivalent to 736 FTE researchers
- ADS contributed $250 million value to astronomical research
- Research activity correlates with country GDP and scientist population

## Abstract

By combining data from the text, citation, and reference databases with data from the ADS readership logs we have been able to create Second Order Bibliometric Operators, a customizable class of collaborative filters which permits substantially improved accuracy in literature queries. Using the ADS usage logs along with membership statistics from the International Astronomical Union and data on the population and gross domestic product (GDP) we develop an accurate model for world-wide basic research where the number of scientists in a country is proportional to the GDP of that country, and the amount of basic research done by a country is proportional to the number of scientists in that country times that country's per capita GDP. We introduce the concept of utility time to measure the impact of the ADS/URANIA and the electronic astronomical library on astronomical research. We find that in 2002 it amounted to the equivalent of 736 FTE researchers, or $250 Million, or the astronomical research done in France. Subject headings: digital libraries; bibliometrics; sociology of science; information retrieval

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Source: https://tomesphere.com/paper/0909.4786